Please ask the responsible Management Team member which class of travel is authorized.
If you wish to upgrade and pay the difference, please print out or save the price of the approved class (for example, economy) and the price of the class you are purchasing (for example, premium economy or business).
Then, after the trip, submit that documentation as part of your expense report so you can be reimbursed for the price of the approved class seat.
Please do not forget to do this. If you wait until after the trip, you will no longer be able to see how much a premium economy seat would have cost.