2020-04-17 : If you reselect which player an attacking creature is attacking, that creature is still considered to have attacked the player as declared, but it is now attacking the new player.

2020-04-17 : Reselecting which player a creature is attacking doesn’t cause “whenever this creature attacks” abilities to trigger.

2020-04-17 : Reselecting which player a creature is attacking ignores all requirements, restrictions, and costs associated with attacking.

2020-04-17 : The player Capricopian becomes attacking may activate its ability, perhaps sending Capricopian right back towards its original destination.

2020-04-17 : The player Capricopian is attacking can’t reselect it to attack a planeswalker instead. If Capricopian is attacking a planeswalker, no player may activate its last ability.