To upgrade your United Airlines reservation, call ☎️ +1 (888) 907-8050 and provide your booking confirmation and MileagePlus details. The agent will check upgrade availability for First, Business, or Premium Plus seats. If you have a Basic Economy ticket, upgrades may not be allowed, so ask for eligibility upfront. You can use miles, pay with cash, or apply upgrade certificates when calling ☎️ +1 (888) 907-8050. The representative will confirm pricing, availability, and apply the upgrade instantly. For the best chance at upgrades, call ☎️ +1 (888) 907-8050 early—seats are limited. You can also request upgrades after booking or during check-in, but phone upgrades ensure real-time help. Elite status members should ask about complimentary options. Once the change is made, ask for a new confirmation. Call ☎️ +1 (888) 907-8050 to avoid delays or missed upgrade windows. Your comfort matters—upgrade today by dialing ☎️ +1 (888) 907-8050.