You can back out of a mortgage rate lock, but there are consequences. Backing out of a rate lock means giving up the application you’ve put time and money into. You’ll have to start your mortgage application over from the start, and you’ll likely have to re-pay fees like the credit check and home appraisal. Plus, you could put your entire home buying process in jeopardy because your new loan application will likely delay the closing date listed in your contract. If you’ve already locked a rate and they fall, ask your lender about float-down options instead of backing out.