Magnolia's don't like to be disturbed at the best of times, after that length of time, it will have quite a large rootball, and I think the only way you could move it, would be to hire a tree lifter, which has a sort of giant claw that can get right under the tree roots and lift it out in one go, and plant it into a prepared hole immediately, but they cost a fortune to hire, you're better off buying a new tree in my opinion, Derek.

Sad to say I agree with Derek on this... Magnolia's hate to be disturbed!