MrsA
Contact the finance company and obtain a copy of the agreement, read it and keep your eyes peeled for a bit that reads something along these lines.
"Termination - Your rights You have the right to terminate this agreement. To do this you must inform us in writing. In return, we are entitled to half of the total amount payable under the agreement and return of the goods in a reasonable condition"
Now the tricky bit, indicated by Maxsteam, is the reasonable condition bit. Most half decent finance companies (certainly ones that I deal with) accept this and get on with it. Other, less desirable outfits may try to get you to pay the outstanding balance in full.
You should have no problem if the car is worth the same, if not more, than the outstanding balance.
As an after thought, can you step in and sell the car for your Dad for more than the amount on the agreement? Are you changing your car? You could trade it in against your new one for example...? Just a thought...
JJ
You gotta tie yourself to the mast my friend, and the storm will end.