What’s the correct procedure for canceling a Non-B Visa when leaving the country? Do you have a to leave on the day it’s canceled or have to extend if you aren’t leaving that day?
Plan is to come back again in the future hence wanting to do it all properly.
TLDR : Answer Summary
To cancel a Non-B Visa when leaving Thailand, it's important to distinguish between the visa and the extension of stay. You cannot directly cancel a Non-B Visa; instead, you must cancel your work permit first. If you are on an extension of stay, you should also cancel that at the immigration office. This can be done in advance, and you do not have to wait until the last day of your visa validity. Once you cancel everything, you can exit the country and apply for a new visa later.