To get your name off a cosigned loan you should go talk to the company who provided the loan and ask them if you can be removed from the loan.
Usually if the payments have been made on time then the lender will usually remove your name as a cosigner upon request.
Another way of getting your name removed from a cosigned loan is to have the person who took out the loan to re finance the loan without a cosigner or with a new cosigner and have your name removed from the loan that way.