The tree can be moved. I agree that the best time to attempt a move is when the tree is snoozing. Anonas are "deciduous" or at least "semi" during cooler months. You'll wind up leaving most of the tree behind, however you'll get to take home what you need. Prune the branches back hard leaving them bare. If possible leave a few nurse leaves here and there. You can also bring down the height to around 6 feet or so. Water ground well around tree in advance, about two foot in diameter. This will help to keep the soil together when trenching and moving plant. If ground isn't too hard dig a trench around and cut through roots with sharp spade or loppers. A walk behind motorized trenching machine might help cut a clean circle around the tree. Trench down about 18 to 24 inches and then start digging under the tree. After awhile you should be able to rock the tree until it loosens enough to be lifted. Have a large plastic bag ready to wrap around root ball to keep it together. Also have a hole ready where you intend to replant. You'll probably loose a fruiting season, but I believe you'll get the tree. I did this with a six foot sugar apple, removed all the foliage, bare rooted it, and transplanted it to a large pot. Sure enough it sprouted new leaves when the weather warmed up.