You've made an offer on a home. The seller accepted it. Congratulations!

Then, a bit later, someone sends you another contract called the Purchase and Sale Agreement, usually shortened to the P&S, and asks you to review and sign it.

A very reasonable question follows: Didn't I already sign a contract to buy the house? Yes, you did.

In Massachusetts, buying a home commonly involves a two-step contracting process. The Contract to Purchase, which most people simply call the "offer," is a binding contract once accepted. The Purchase and Sale Agreement that generally follows is a much more detailed contract governing the transaction as you move toward closing. And there's something important to understand about that second contract: It may not simply repeat what you already agreed to.

First, Your "Offer" Was a Real Contract

This is important enough to repeat. When we casually say, "We're going to write an offer," it can sound as though you're simply proposing a price and nothing becomes official until you sign the P&S.

That's not a good way to think about it. The Contract to Purchase is an actual contract. Once properly accepted, it creates binding obligations for the buyer and seller according to its terms. In fact, the Massachusetts Association of REALTORS® Contract to Purchase says "BINDING CONTRACT" right at the top. It also states that once the seller's written acceptance has been communicated, the accepted offer forms a binding agreement.

So the P&S isn't the point when your casual offer suddenly becomes serious. It was already serious.

Then Why Do We Need Another Contract?

Because there is considerably more to a real estate transaction than: I'll buy your house for $X and close on this date. The P&S is generally much more detailed than the Contract to Purchase.

For example, the standard Massachusetts Association of REALTORS® P&S addresses the property and what's included in the sale, purchase price and deposits, escrow, closing, title, possession and condition, adjustments for items such as taxes and fuel, buyer-broker compensation, default, inspections, financing and notices between the parties.

And the MAR form specifically states that the P&S supersedes and replaces obligations made in a prior Contract to Purchase or agreement for sale.  That's a very good reason to pay attention to what the new contract actually says.

There Isn't One P&S That Every Massachusetts Buyer Signs

The Massachusetts Association of REALTORS® has a standard Purchase and Sale Agreement, but that doesn't mean it's the document you'll receive.

In many transactions, the initial P&S is prepared by an attorney, often the seller's attorney. Different attorneys use different forms. While usually similar, there is a lot of language in the 6-10 page document. Pay attention to what those pages actually say.

The P&S Can Contain Things You Never Discussed

This is one of the most important things for buyers to understand. The P&S isn't necessarily just a longer version of the Contract to Purchase. An attorney-drafted agreement may contain provisions that weren't discussed when you made your offer. It may address situations that weren't covered in the original contract at all.

And sometimes a proposed P&S may even contain language that changes a term the buyer and seller already negotiated. That doesn't automatically mean you have to accept the change. It means you need to notice it.

The seller's attorney may prepare the first draft. Your buyer's attorney reviews it, may propose changes and may prepare a Buyer's Addendum containing additional or modified provisions.  There may be some back-and-forth between the attorneys before the final agreement is ready for everyone to sign.

Please Read the P&S Yourself

Your attorney should review the Purchase and Sale Agreement. We also try to read it from the real estate side of the transaction.

But you should read it too. Changes and additions aren't necessarily accompanied by a convenient page titled: "HERE'S EVERYTHING THAT'S DIFFERENT." You may need to find them by actually reading the document.

Keep your accepted Contract to Purchase handy when you review the P&S. You don't need to understand every piece of legal terminology. That's what your attorney is there for. But you do know the deal you made.

• You know the purchase price.
• You know the closing date you negotiated.
• You know what was supposed to remain with the property.
• You know the contingencies in your offer.
• You know whether there were particular terms that mattered to you.

If something in the P&S doesn't appear to match what you thought you agreed to, say something.

"It's in the P&S" Doesn't Mean "That's What I Agreed To"

• If the closing date is different, ask.
• If the financing terms look different, ask.
• If something you specifically negotiated seems to have disappeared, ask.
• If there's a new obligation you don't remember discussing, ask.
• If you encounter a paragraph that makes absolutely no sense to you, definitely ask.

Your attorney may explain that the language is customary and recommend accepting it. Your attorney may recommend changing it. Or you may have identified an actual difference that needs to be resolved with the seller.

The fact that language appears in a proposed contract doesn't mean you shouldn't question it. That's precisely why contracts are reviewed before they're signed.

What Does My Buyer's Attorney Do?

Your attorney represents your interests, and possibly the interests of your lender, in the legal aspects of the transaction.

If the seller's attorney prepared the P&S, your attorney isn't simply proofreading someone else's document and telling you where to sign. They're reviewing a proposed contract that may ultimately replace the Contract to Purchase you already signed. Your attorney may negotiate language, propose changes, add provisions through a Buyer's Addendum and explain the legal consequences of the agreement to you.

The standard MAR P&S itself ends with a very direct warning:

"UPON SIGNING, THIS DOCUMENT WILL BECOME A LEGALLY BINDING AGREEMENT. IF NOT UNDERSTOOD, SEEK ADVICE FROM AN ATTORNEY."

We take that seriously.

What Is My REALTOR® Looking For?

Your agent isn't your attorney and shouldn't give you legal advice. But your agent has been involved in the real estate negotiation from the beginning.

We know you, and are familiar with your offer. And sometimes that makes another set of eyes useful. If we see something in the P&S that appears inconsistent with the real estate terms we negotiated, we can bring it to your attention so you can discuss it with your attorney. The goal isn't to replace your attorney's review.

It's to have everyone on your team paying attention.

I'm Moving Here From Another State. Is This Normal?

For Massachusetts, yes. But your confusion is completely understandable.

Real estate practices vary significantly from state to state. You may have purchased a home somewhere that didn't use this same two-step process. You may also be coming from a state where attorneys have a much smaller role in a typical residential transaction.

So when we tell an out-of-state buyer: "Your offer has been accepted. Now the attorneys will work on the P&S," we understand why the response is sometimes:

"Wait. Didn't I already sign the purchase agreement?"

You did. You're now moving into the next stage of the Massachusetts process. We'll explain what happens here and who is responsible for each part.

What Happens After the P&S Is Signed?

Once the final P&S has been agreed upon and signed, the transaction continues toward closing. Depending on your purchase, that may include mortgage underwriting, appraisal, title work, satisfying contractual deadlines and other closing preparations.

The P&S establishes many of the rules and deadlines governing this part of the transaction. For example, the MAR form contains detailed financing provisions, including a mortgage commitment date and notice requirements.

Those dates matter.

Respond promptly when your lender, attorney or agent asks for something, and ask questions when you're unsure what you're being asked to do. This is not a particularly good stage of the transaction to disappear on a two-week wilderness retreat without cell service.

You Don't Need to Become a Real Estate Attorney

When the P&S arrives in your inbox and it's considerably longer than the Contract to Purchase you signed a few days earlier, don't panic. You aren't expected to understand Massachusetts real estate law because you decided to buy a house here.

That's why you have a team. Your REALTOR® helps you navigate the real estate transaction. Your lender handles your financing. Your attorney handles the legal side of the purchase.

But there's one person who should never be left out of the review process: You. Read your contracts.

Your agent is reading them from the real estate side. Your attorney is reviewing them from the legal side. But nobody has more at stake in understanding what you're agreeing to than you do. If something looks different from what you remember negotiating, or you simply don't understand it, ask before you sign.

Because when it comes to a Purchase and Sale Agreement: "It's in the P&S" isn't the same thing as "that's what I agreed to." And nothing is a substitute for knowing what you're signing.