After the leaves have fallen, so on a mild day in november or december, certainly before march.
I take it that its a youngish tree, prepare the site well and take the biggest rootball possible, remember it will need lotsof water through the coming year.

But if its been in for more than two or three years it might not survive the move.

Transplant it in the winter months when the tree is dormant. Pick a frost-free day, make sure that the root ball has enough water and dig in well rotted mulch for extra moisture retention and nutrition.

Thanks everybody,I might just go in for another pear tree to be safe .

That will help pollination too Brian