Mike here on Phuket u will need more the. 15 days some officer say 21 days left on your tourist visa to change it to a NON O, I advise u to fly direct with firefly to Penang and get it there in 2 days, if you a Have all papers ready it is easy. And if u not want to got by yourself I will send a PM for an advice over there.
If U have the NON o you can easy transfer it to a retired visa here in Phuket town, patong will,not do it !
To make it easier for u....just go to an consulate in Penang. Or Vietnam to make a NON o because here it will need about 2 weeks or more...so to give U time just make a short trip....
2. U need the funds in a bank account and a letter from it, or a letter from your embassy that show u have enough income , like from renting out, or your pension is enough ...please look at the consulate witch paper u need ....
Coming beach (
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days) u have enough time.....
For the fees look at the official Imigration web page