Endorsements for domestic tickets really depends upon the agent. If a customer walks up to me with a full fare ticket from another airline and wants to get on a trip, does anyone really think I would refuse that? Unfortunately on the other hand, I have had other carriers i.e AA, US request endorsements on full fare tickets, when there are no restrictions on them, and then refuse to accept them. I am still trying to figure out that. Even if the other airlines ticket is a nonrefundable ticket, if I have space on the aircraft I will still typically take the ticket. For what reason? Give the passenger something to tell other people what United did for them. Generate revenue, even if we only get half of the value, half is better that none at all, and lastly we have taken someone from travelling on a another airline,and I will fight tooth and nail to take a passenger from the competition.And, don't laugh, I still think United is the best out there, considering everything, the good and the bad, and from dealing with other airlines over the years, believe me I have seen a lot worse.So if another airline is giving you a rough time from accepting a full fare ticket, tell them to lighten up and stop being so picky. It ain't raining money these days in the airline industry.