So do I understand correctly that if I want to use my miles for an *A partner award flight for someone else, and I am not travelling with them, only a TK ticket office could complete the reservation.
Depending on the process of the selected ticket office, this may be possible remotely (by sending the required info/forms to the ticket office) or only possible by a physical visit to the ticket office. Correct?
Yes, you are correct. You would need to contact a sales office and depending on their process you could complete the ticketing process remotely by phone/e-mail or you might need to visit them in person.