I would go to your nearest immigration office ....in Thailand it’s always better to arrive at the departing airport with all your paperwork in order ....
Be very careful if or when you book a flight with any airline a while in advance ....they can cancel anytime because airlines apparently are a law unto themselves ....I’m still waiting for a
*****
baht refund for over a year now from Thai AIRWAYS WHO CANCELLED MY FLIGHT 3 HOURS AFTER BOOKING...and I’m sure that they knew that that flight would not take off.....
Hi Murray I’m a retirement visa holder married to a Thai lady who is an expert in Health insurance...she is an agent for a leading company here in Thailand...give her a call on 0805899602 her name is Alisa