"Not quite sure what you're asking. If you have a non-O then you already have a retirement visa. The only thing you can do now is to apply for the 1-year extension.
If you leave the country you will forfeit your retirement visa and will have to start over. You cannot live in Thailand as a tourist, so you either need to return and apply for a new non-O visa at immigration, or go to an embassy in a neighboring country and apply for a new non-O visa there. You cannot extend a visa outside of Thailand."