Do one of the following (either will use your shot):
1] kill target player. Player won't flip publicly (but role and aligment will be revealed to you). Player can't use any abilities available in death, if applicable. Other players who are able to target dead players (for example revivers), can't target this player.
2] get rid of target dead player. Player can't use any abilities available in death, if applicable. Other players who are able to target dead players (for example revivers), can't target this player.