I purchased a flight in late 2023 for travel in summer 2024. Unfortunately, I was unable to travel or use the flight credit, as I already had other trips planned. I rescheduled the flight online for 2025 and paid the fare difference since the new flight was more expensive. I received a new ticket number but retained the same confirmation number.

When I checked online, there was a note indicating the ticket needed to be reissued and to contact an agent. United is now stating that the ticket is only valid for one year from the original 2023 purchase date, even though I changed the flight online and received a new ticket number.

Is this correct? If not, is there an email or contact to escalate this issue? I believe the ticket should remain valid since it was successfully changed online.