copy keyframes from another objects and then make them unique

I copied the keyframes from a camera to another camera with CTRL+L (Make links) -> Animation Data.
I want to brake the link so I can modifiy some of the keyframes to not affect the first camera that I copyied the keyframes from. I see now if a change the rotation on the second camera , it affects the rotation on the first one. I don’t want that.
How can I do brake the links between the two animation data or how can I make the second camera animation unique?

Object / Make Single User (shortcut U)

It worked. By mistake I hit L (make local) instead of U (make single user).

here’e a video for those who didn’t know about this feature: