Many actions in combat (like making an enemy fall prone), can give an edge to your teammates (in this case, melee advantage) until the enemy's turn (in this case, he would get back up to end the condition). Such actions are the most useful when your turn is right after the enemy's turn, so that all of your teammates can benefit from the edge you give them.
Contrary to the Ready Action (which enables to delay an action to be made after a specified trigger), what I'm seeking here is for a character to delay his entire turn in the initiative order. Is such a thing possible ?
Example 1 : The initial order is Bob, Enemy, Friend 1, Friend 2. Bob wants to delay his turns in the initiative order to do as if his initiative roll had placed him right after "Enemy" in the cycle : Enemy, Bob, Friend 1, Friend 2.
Example 2 : The initial order is Friend 1, Friend 2, Bob, Enemy. Bob wants to delay his turns again, even if, this time, he won't do anything for the first round. The second round's order would then be : Bob, Friend 1, Friend 2, Enemy.