I just renewed my passport in Bkk and have a letter from my embassy for the Chiang Mai immigration from last week. How many days do I have to go to change my visa on the old passport to the new one, now that i am back in Chiang Mai. In bed with a terrible back. Would this look like an overstay, if I go later this week ? thanks
TLDR : Answer Summary
After renewing your passport and having a letter from your embassy, you should be able to visit the immigration office later this week to transfer your visa to your new passport without it being considered an overstay.