What are the requirements to switch from a volunteer visa to a retirement visa in Chiang Mai?

If it's an extension you got from immigration in Thailand, and if it's for a reputable organization (the volunteer work). It is possible to just change the reason for your extension. They will cancel your current extension and immediately stamp the new reason (retirement) extension in your passport for 1900 baht. You will lose any remaining days on your current extension and the new year extension starts the day they do it.

If you are on still on a visa, that you got outside Thailand, or the initial 90 day visa gotten inside Thailand (no extensions yet) it is not possible to change the reason for extension until you have had at least one extension for the same reason as the visa was given for (volunteer)

go out come back as a bloody tourist, put 800k in the bankl, get an agent to help u with the rest to get a 12 month extension of stay!

Unless you have a volunteer visa 'Extension' you cannot 'switch' to anything.

It's even debatable if they will allow it from an extension right now.

Volunteer visas are being scrutinized right now…it might hold up a retirement visa

800k is from overseas and can be seen on your bank statement as such ?