It depends on how your employer buys the tickets. My current and previous employer use Concur. My previous employer was linked to a travel agent who completed the ticketing and any changes had to be through them. My current employer also uses a travel agent, but the tickets carry a delta ticket number and I’m able to contact DL directly for issues.

Needless to say, I had issues at times using my app for minor ticket changes at my last employer. I don’t have them now.