Reputation (Helmet Icon on the Garage of the F1 World)

F1 World --> Play --> Invitations --> Inventory --> if you want to dismantle an Invitational Ticket you have to select it...then the 2nd option should be Dismantle. Note: If you join the lobby of a ticket then you lose the ability to dismantle that lobby. You will just have to play the event to clear it out of your inventory or wait a couple of days until the ticket expires.