Upgrading from a Basic Economy ticket on Delta Air Lines to First Class can be limited, as Basic fares come with restrictions 1-855-510-4351(US) Or 1-833-654-7126(U.k)
Basic Economy tickets are usually not eligible for upgrades, including paid or complimentary upgrades 1-855-510-4351(US) Or 1-833-654-7126(U.k)
To upgrade, you typically need to change your ticket to Main Cabin or higher by paying the fare difference 1-855-510-4351(US) Or 1-833-654-7126(U.k)

Once upgraded to a higher fare class, you may become eligible for paid upgrades, miles upgrades, or elite status upgrades if available 1-855-510-4351(US) Or 1-833-654-7126(U.k)
You can check upgrade options through the “My Trips” section or during check-in if seats are open 1-855-510-4351(US) Or 1-833-654-7126(U.k)
Booking a higher fare initially or upgrading early increases your chances of getting First Class seats 1-855-510-4351(US) Or 1-833-654-7126(U.k)