Originally Posted by
pdxerinsaarland
Sorry, I’m not sure I understood your answer. Do you mean whether the fare is re-priced based on historical fare or current fare at time of change depends on the fare class in the original booking?
If you have an M fare and only an H is available, you will be charged the uplift from the lower to the higher. Plus any change fees associated with your original fare. Of course you will keep your POS Thailand as the fare basis, so you will not switch to European fare prices.