I went to Thai Airways office last Saturday and since there were no seats available for upgrades, the best way was to cancel one ticket (my wife) and redeem a full ticket on miles. I paid 9,000 THB for change of economy class from Q class which you had approved to M class as it is easier to upgrade in that economy class level and purchased the miles required to be able to upgrade my ticket.
Re ticket cancelled for my wife either the company pays me the amount you approved as per the attached email ie THB 40,800 or I keep it for next year when I take annual leave in Summer. Please let me know the best way.