A contract is one thing, an escrow is another.............
So many times I've seen the case where a principal and their agent fill out a cancellation of contract, and once it's signed, they think it's all over and done.
What you need to keep in mind is that the contract between a buyer and seller is one thing. The ESCROW, however, is not one in the same. In addition to cancelling a contract, you must also cancel the escrow. Otherwise, escrow does not have the ability to appriopriate funds and or take any remedial action according to the cancellation of the contract.
That works in reverse also. If you fill out an escrow cancellation form, that does not necessarily cancel the contract. You need a cancellation form for the contract as well.
Another small thing to keep in mind is that any amendments to you contract do not affect your escrow unless, of course, you notify escrow of the amendment. Ideally, with enough time to take appropriate action based on the terms of the amendment.
I've seen it often enough where there are credits issued or perhaps a price reduction that is mutually signed by buyer and seller, yet no one has communicated that to escrow, which ends up in a last minute scramble at close of escrow which sometimes results in unecessary drama.