A rate lock extension is when the lender adds extra days to your rate lock period. Ask the loan officer for an extension if your lock will expire before your closing date. Make the request before the lock expires.
In some cases, the lender will charge you a fee to extend the lock period. The extension fee might be cheaper than relocking the loan at a higher interest rate.
For example, we charge 0.02% of the loan amount per day. So a 7-days rate lock extension on a $100,000 loan would cost $140.