I have a Blue fare that was booked through work that I'd like to upgrade to Mint (paying whatever fare difference) but when I called JB they told me the only way to make the switch is to cancel my fare and rebook in Mint. Is this normal? I could've sworn I was able to pay for an upgrade before, seems odd to have this restriction.
Fairly sure that's normal. If you can't go with the cancel & rebook because of work, there is the option to take the upgrade at the gate (with the fee 599? 649?).