Not without significantly stressing the tree (though to be fair, crapemyrtle tolerate a lot of abuse). This amount of size reduction sounds too drastic for a plant this size, but you should consult a certified arborist or two to be sure. They may recommend a pruning technique that will minimize tree health impacts while maximizing how long each cut lasts. (Pruning triggers growth, so this coupled with the tree's innate genetic programming to grow this size will only result in its return to this height eventually. Thus, it would need to be trimmed annually or nearly so to maintain that new height.) Some arborists work as employees of a tree-care company while others consult independently.

The alternative is to replace the tree with a shorter-growing plant or another cultivar of crapemyrtle which matures smaller. There are dozens of options on the market today since crapemyrtle breeding has produced an explosion of introductions in the past decade. If you are open to it, consider a native species alternative instead of crapemyrtle so it may better support wildlife. Most "small" trees still mature in the 20-30' height range, but some selections are more compact than others and may even stay closer to 15' or so. Plus, it will be easier to do minor trimmings as a young tree matures to limit its height than it would reducing the height on a mature tree. Otherwise, large shrubs may be a suitable substitute instead, as they tend to mature in the 8-12' range, some of which can be trained to look like small trees by removing lower branches as they age.

Miri