“camera actor a child of my character” hmmm? what are you trying to do 
Just disable “Auto Manage Active Camera Target” in Player Controller and change view target to camera , if you want to change camera component inside the actor in blueprints you need to disable one camera compoennt and enable other camera component.
But if you want to change view to different actor just change view target, it a player controller function so get player controler and and do “set view target”