Camera following player, how do get it to stop after the player falls?

Hey There pees I have a question about camera... I'm using Cinemachine to have a smooth cam but when let say when the player falls the camera falls with him. So my question is how can i get the cam to stop following the player at a key point? I have a box collider there so when player hits it the cam doesn't follow. But im lost at what to do. Thanks for the help!