Children > Chat

When you look at your Child's Chats with one of their Friends, you can't Chat with them yourselves, but you will see a log of all the Chats that they have had so far with your Child.

You can review any interactions and decide if the Chats are approriate. If you don't like the Chat and you feel you need to intervene for you Child's protection, you can turn off the Permissions for your Child to use the Chat feature (see Tutorial). And you can always Delete the Friend.