How do I handle reentry permits and visa stamps when transferring to a new passport in Thailand?

When transferring long stay visa stamps to a new passport, you should visit your local Thai Immigration office to request the transfer of stamps from your old passport to your new one. You will need to purchase a reentry permit, which will be stamped in your new passport. It's important to carry both passports when exiting Thailand, as your most recent entry stamp is in the old passport. You will also need to include the TM6 arrival card number from your old passport when filling out the reentry permit form. The TM30 is already recorded with the Thai Immigration office.