Hello, I was very confused about this thing and reading "opinions" online just made me more confused. So I thought I should share my experience with it in case it may help somebody.  I have a tourist visa that was expiring on 29 March (included the 30 days usual extension). I asked the embassy for the letter explaining I was caught in Thailand with no possible flights out. I went to Chaengwattana Immigration Office and they granted me the "extraordinary" extension. HOWEVER, they required