Your joint training exercises allow you to unify your efforts with allies in combat. As a result, you learn one Joint Fighting Style option of your choice. If you already have a Joint Fighting Style, the one you choose must be different. In addition, under normal circumstances your space does not count as difficult terrain for allies entering it.

Whenever you reach a level that grants the Ability Score Improvement feature, you can replace this feat’s Joint Fighting Style with another Joint Fighting Style that you don’t have.