You probably already know this, but just in case, here is a bit from the Martin website:

Obtaining Warranty Service
If service becomes necessary write to our Customer Service Department, P.O. Box 329, Nazareth, Pennsylvania 18064, or call (610) 759-2837 from anywhere in the United States or Canada, weekdays between 8:30 a.m. and 4:00 p.m., Eastern time, or have your dealer do so on your behalf. A complete description of the problem should be provided to us. Our Customer Service Department will then provide you with the name and address of the authorized warranty service centers nearest to you. Repair work can be performed at authorized warranty service centers located throughout the United States and Canada. In order to take advantage of your warranty coverage, you must take the instrument, or deliver it prepaid, to an authorized warranty service center.