2014-11-07
Raving Dead must attack the chosen player if able, not a planeswalker controlled by that player.

2014-11-07
If, as attackers are declared, Raving Dead is tapped, is affected by a spell or ability that says it can't attack, or hasn't been under your control continuously since your turn began (and doesn't have haste), then it doesn't attack. If there's a cost associated with having Raving Dead attack the chosen player, you aren't forced to pay that cost, so it doesn't have to attack that player in that case either.

2014-11-07
If Raving Dead can't attack the chosen player for one of the above reasons but it can still attack elsewhere, you may choose to have it attack another player, attack a planeswalker, or not attack at all.

2014-11-07
If your turn has multiple combat phases, Raving Dead's ability triggers at the beginning of each of them. Ignore any choices made during previous combat phases that turn.

2014-11-07
The last ability triggers and resolves after combat damage has been dealt. For example, if an opponent has 17 life and Raving Dead deals 2 combat damage to them, they will end up at 8 life.