How can a co-signer get possession of car if the other co-signer has defaulted on the loan payments?

Question Details:

The person having the car has defaulted on several payments and repossession is looming. We are listed both as "OR" on the documents. Also registration hasn't been payed for 6 months now (just found out) and there are unpaid parking tickets. If I would pay off the car loan at once, would I get the title? If so, how can I get the car if the person is not returning it on free will? Important Notice