20 C.F.R. § 408.201
You are qualified for SVB if you meet the requirements listed in § 408.202 and if none of the conditions listed in § 408.204 exist. However, you cannot be entitled to receive benefits for any month before the first month in which you reside outside the United States on the first day of the month and meet all the qualification requirements. You must give us any information we request and evidence to prove that you meet these requirements. You continue to be qualified for SVB unless we determine that you no longer meet the requirements for qualification in § 408.202 or we determine that you are not qualified because one of the conditions listed in § 404.204 of this chapter exists. You continue to be entitled to receive benefits unless we determine you are no longer residing outside the United States.
20 C.F.R. §408.201