It can be dangerous to move a tree that size. You need to go out to drip line (the edge of leaves) and dig around from that point, but you can damage the fibrous roots and ultimately kill the tree. My advice would be to get a horticultural specialist in. Visit your local garden centre or ask friends to recommend a reputed arborist. Evergreens are generally harder to move, but the best time would be the middle of winter when the tree is dormant.
