I only upgraded my ticket to be able to choose seats close to my partner and what happened at the gate? Of course they changed my seat without ever asking me if it's ok. No "I'm sorry" or anything like that. Their only response was rude "nothing we can do about it" even though they gave my seat to some other person. I tried to get compensation back but contacting them via complaint form is pointless, no response for two weeks already. I see I'm not the only person experiencing similar thing - I don't know how it is legal to change people's seat after they were paid for. Now I'll do everything to avoid Delta.