It's a bit late in the season to do so now. Pruning during the growing season actually stimulates the development of new growth, which may not have sufficient time to harden off or mature before cold weather sets in and can result in damage or dieback to the tree.

Ideally, you want to prune when the tree is dormant or just before it emerges from dormancy....,late winter or early spring. You can also prune in summer and many fruit trees (and some ornamentals) are recommended to be pruned then but I wouldn't advise doing so after mid July at the latest. And you shouldn't take off as much in summer as you can when the tree is dormant. No more than 15-20%.

Ok. I will wait until late winter. Thanks.