How do I change my sponsors?

So I hit the randomize button when creating sponsors for my car and I've completed two of these challenges, but I cannot see a way to change them.

Do I need to complete all three challenges before I am allowed to change them?

I am trying to change them from the my vehicle menu, under sponsorships.

Solution 1:

No, it's not possible to change your sponsors at will, and completing the sponsor objectives will not allow you to change the sponsors either.

You are granted the opportunity to change your sponsors at the start of each World Racing Series season and during this time you're normally offered additional sponsors and locations on your car to place sponsor logos.

You can change your sponsors on the 'My Vehicles' menu under 'Customise Player Livery' on the 'Sponsors' screen.