After checked with TG, I do not cancel your ticket as the officer has suggested that if you still have a plan to Colombo, you should keep your ticket for using the next trip. The fee for rebooking & reissuing the new ticket at THB 1,200 per changes.
If you don’t have any plan to go there and would like to cancel this trip indeed. We can cancel this ticket by phone only. But we can’t refund anything by phone. You or someone must go to TG office in Yangon to do refundable . (If you ask someone to do it for you, you must prepare your original eticket with POA for your representative also).