Sometimes things change a little bit in the last few days before closing. For example, if the seller hasn't fixed something they agreed to fix, there may be a change. The seller may give you money to put towards your closing costs (know as seller credits) instead of trying to make the repair before closing.
If something important changes about your loan, you will receive a new Closing Disclosure. In limited circumstances, the law requires that you receive a full three business days to review the new Closing Disclosure before closing.
Don't be afraid to ask a lot of questions. A mortgage loan is a big financial commitment, and you have a right to understand what you're signing up for. Don't sign a document until you're comfortable with what it says. If the problem or confusion is about the terms and conditions of the sale, ask your attorney. If the problem or confusion is about your loan, you'll need to talk to your processor.