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Once you have decided on the best lender and/or interest rate, request to see a blank copy of the lender's rate lock form, if possible. This will give you an exact sense of what to expect before submitting your own application. If you have time, you can have the blank form looked at by your realtor and/or real estate lawyer for approval. If your lender charges a fee for locking in a rate, make sure that you understand the fee amount and how it is related to the conditions of the rate lock (such as its length). Rate lock fees can be several hundred dollars. In many cases, a rate lock fee might be refunded, unless your mortgage application is canceled. When you are ready to lock in your rate, contact your lender. Depending upon the institution, you may have several ways to make the request (phone, fax, in-person visit, etc.). However you initially contact the institution, it is important to get the request in writing. Send a document that specifies the rate you would like to lock your mortgage in at, and any applicable points or other terms. Make sure that your request is signed and dated by you and any co-borrowers. Most lenders will connect you with a mortgage consultant or office to contact when you are ready to request your rate. Your realtor or real estate attorney can help you in preparing this request. When sending your request, make sure that you have completed any application and made any deposit your lender requires to get a mortgage. Your lender should send you a letter confirming your request for a rate lock within a specified period (usually a brief one, such as 5 days). If your request is approved, you should get a written confirmation from your lender. Make sure that the confirmation displays: The agreed-upon rate Whether or not the rate is guaranteed The property address The loan amount and program (i.e., the mortgage period) The lock in fee The lock in date The lock in expiration date Any special terms or conditions The lender's and borrower's signatures Making a rate lock request and even being approved for one are not absolute guarantees that an interest rate will not change. In certain situations, you can re-negotiate the rate lock terms; in others, you will either have to accept the new rate or seek a new mortgage. For example: If rates change in between making a lock in request and its approval, the original request will be void. You will then have to re-negotiate the request, if desired. If you change the kind of loan you are requesting, or the terms of the loan (for example, the amount of your down payment), your rate can change. Your rates can also change if your credit score rises or falls during or after the process of making the rate lock request. If your income cannot be verified, lenders may not be able to honor a rate guarantee. A change in the appraised value of the home you are seeking to buy can also result in a change to your rate.

Summary:
Review your lender's rate lock form. Know what the fee will be, if any. Request the rate lock. Get the rate lock agreement in writing. Know when your rate may change even after a rate lock request.