Hello! I've noticed an actor's cover photo that is quite old, how do I update it to a new one? I don't see any place to edit the page... Thank you in advance for the help!

are you currently using your phone? If yes then rotate your phone, you can see the edit option at the top right of the page. 

 https://i.postimg.cc/NjC7FmK5/Ss.jpg

Don't forget to give them the source link of the photo and reason for changing the Cover Image in the Additional notes.