Unblocking a user from your personal account
If you've mended fences with a GitHub user you've blocked, you can unblock their account.
When you unblock a user, they'll be able to invite you to be a collaborator to their repositories. If they @mention you anywhere on GitHub, you'll receive notifications.
In repositories you own, the user will be able to collaborate normally.
You can unblock a user in your account settings or from the user's profile page.
Unblocking a user in your account settings
In the upper-right corner of any page, click your profile photo, then click Settings.
In your user settings sidebar, click Blocked users.
Under "Blocked users", next to the user you'd like to unblock, click Unblock.
Unblocking a user from their profile page
Visit the user's profile page.
In the left sidebar, under the user's profile picture, click Unblock or report user.
Click Unblock user.
Tip: Settings that were removed when you blocked the user, such as collaborator status, stars, and follows, are not restored when you unblock the user.