How to select the seat if you can't edit traveler information?
Trying to select seats in business class for flight on TG. When I put the Thai record locator it tells me

4 warnings

Warning

• Your updated "CONTACT INFORMATION" is required before adding any service(s). Please click "Modify traveller details" below to process
• Your updated "CONTACT INFORMATION" is required before adding any service(s). Please click "Modify traveller details" below to process
• Your updated "CONTACT INFORMATION" is required before adding any service(s). Please click "Modify traveller details" below to process
• To change your flight(s)/date(s) of travel, please contact the THAI office at your point of departure or your travel agent (if the booking was made through a third party).

I go to the Contact information, I can add passport numbers for my wife and myself, the only thing I cannot edit is Mr. or Mrs. which is greyed out and it tells me that this field is mandatory. Without that I can't go to the next tab which is Services.

At Services I see: For purchased add-ons such as Preferred Seat / Additional baggage and Etc. If passenger need to change any (the date, the flight, the seat) please contact THAI worldwide office or THAI Contact Center (+66-2-3561111)

So I can't add services if I can't add Contact Info and the catch 22 is closing again on itself...