How do i smooth my camera when i possess another character

You would need to override your default camera behavior with a custom script. Depending on the perspective of the game (first person/top down/etc.), you would do this in different ways.

For instance, in a top-down action game I’m working on, the player characters do not have a camera attached to them. Instead, I have a custom actor with a camera that calculates its position as the average between all active players.

There are a few settings you’ll have to tweak to make sure that the engine uses your custom camera. But that once again depends on what you’re trying to do.