Destroy player on spawn if he already exists in scene

i have a multiplayer game.
i have 2 character classes, they are selected and spawned when he presses a button.
i made it possible to bring back the class buttons after the player has already spawned, in order to change classes during the game, however doing this leaves the old player prefab in the scene and i end up controlling it and the new one. How can i destroy the old player when the new one loads?

Google Unity singleton pattern