Suppose that at a regular REL event, you have an experienced player, and an in-experienced player, and the in-experienced player has a gideon's lawkeeper on the battlefield.
The experienced player declares the beginning of the combat phase, and the game then proceeds to the Declare Attackers step. the in-experienced player tries to tap down an experienced player's creature during the Declare Attackers step.
The experienced player explains to the inexperienced player that in order for the tapping to stop the attack, he has to do it during the Beginning of Combat step.
Are the players authorized to agree to re-wind the game back to the Beginning of Combat step so that the in-experienced player can do his action correctly, or would the players have to ask a Judge's permission?