If you no longer want to be friends with someone else on Here, all you have to do is select the unfriend button. When you unfriend someone, it will also prevent them from being able to direct message you.
Note: You can always add them back as a friend later if you made a mistake and it will restore your direct messages.
Follow these steps to Unfriend:
Step 1: Click on your profile icon in the top right of any room or lobby
Step 2: Select the Friends button to pull up your Friends List
Step 3: Select the 3 dots in the corner of the user you want to unfriend
Step 4: Choose Unfriend off of this menu. Confirm that you want to unfriend this user by selecting the red unfriend button that follows.