Recently, in the FL I attached a colleague to my PNR, I flew a day before him and we returned together.

I managed to choose seats for the outbound for him (same cabin.... differnt day....)

He was even opuped (as a blue....l) We both were opuped upon the return (TLV) if I was opuped alone he would have gotten my seat. Cause I don't care....)

I assume face to face in a lounge, with the random agent there, with a smile, more can be achieved than over the phone.