What I did years ago (America) was booked the round trip, came and did 2 30 day extentions, but within the first 30 days, for $200 charge, moved the return flight up to the date that was 90 days after flight to Th. On the 4 trip, to stay in country on retirement stamp, I notified the airlines that I wanted to open extend the return trip. For $200. they gave me a 1 yr extension.