Organization owners can unblock a user who was previously blocked, restoring their access to the organization's repositories.
When you unblock a user from your organization, they'll be able to contribute to your organization's repositories.
If you selected a specific amount of time to block the user, they will be automatically unblocked when that period of time ends. For more information, see "Blocking a user from your organization."
Tip: Any settings that were removed when you blocked the user from your organization, such as collaborator status, stars, and watches, will not be restored when you unblock the user.
In the top right corner of GitHub, click your profile photo, then click Your profile.
On the left side of your profile page, under "Organizations", click the icon for your organization.
Under your organization name, click Settings.
In your organization's Settings sidebar, click Blocked users.
Under "Blocked users", next to the user you'd like to unblock, click Unblock.