Ending Players Turn

Hello all i am currently trying to create a multiplayer turn base game i can get everthing to set up fine and i can get my server to switch turns to the client but i can not get my client to switch turns back to the server. I am using a widget that has a end turn button on it when i click the button it cast to the game state and runs a funtion on the server to end the players turn. As i said this works fine from server to client but not client to server can some one help me out