As has been posted many times, there is no "transfer" or "conversation" of foreign licenses to FAA at the ATP level (unless it is a Canadian license.) You have to complete the same ATP Certificate Training Program, pass the written and pass a checkride. If a type rating is involved, there has to be a record of ground and flight training. The ONLY thing you get from holding a foreign ATP is you are allowed to skip getting the FAA commercial and private certicates which is the normal path to a FAA ATP.