@J ********
as soon as your money has been in your account for over two months, and I hope it came into your account from overseas as they check closely, go to your bank, and get two letters from them. One being a combined deposit statement covering the last three months, or back to when the money was deposited into your account (they require two months, but it's good to have an extra then there is no confusion). The other letter from them basically states that it is your account, in your name only. Both have to be on bank letterhead. Within seven days after you get these, make a copy of your bankbook, every page, and on the day you go to immigration update your bankbook, and make a copy of the last page, and your data page. You can update it by making a transaction, withdraw/deposit a few baht, then update the book. Make a copy of your passport data page, entry stamp page, and visa stamp, and date page. Take all this to immigration and apply for your type O retirement visa extension. There might be something else certain offices want, but this should get an extension stamp in your passport.