Team Fighter (5e Feat)

You fight for your friends. Your priority has shifted from your success in battle to the success of others. You gain the following benefits:

Your Dexterity or Constitution score increases by 1, to a maximum of 20.
Whenever you roll for initiative, choose a party member within 5 feet of you. While you are within 5 feet of them and they haven't received the Team Fighter feat, you gain the following benefits:

The chosen party member gains a +1 bonus to their AC.
When the chosen party member hits a creature with a melee attack, you can use your reaction to make a melee attack on the same creature.
If the chosen party member is targeted for an attack by a creature you can see, you can use your reaction to change the attack target to you.