You should file a Form I-131 for a Refugee Travel Document before you leave the United States. USCIS recommends that you file the form at least 60 days before you leave the United States. If you do not file for a Refugee Travel Document before you leave the United States, a USCIS office overseas has discretion to accept your application. You may only apply if you have been outside the United States for less than one year at the time of filing. You should not, however, assume that an overseas office will automatically exercise this discretion, particularly if it is evident that you could have filed your Form I-131 before you left the United States.