Ward owners can add or remove a player by Steam ID.
Use /optsteam followed by a player's numeric Steam ID in chat to choose an account. Then aim at a ward you own: its Permit or Unpermit prompt names that ID. Press the shown Permit key to request the change. This lets you manage permission without waiting for the player to visit the ward. Check the ward's permitted-player list after the update. Use /optsteam 0 to clear the selected account.