Board Thread:Support Requests - Community Management/@comment-27364552-20140726214844/@comment-4143277-20140726215022

You can unblock a user by navigating to their contributions and clicking the "Unblock" option. If this does not work, and they appear to be blocked but with nothing in their block log, then they are global blocked and that is not within any local admins jurisdiction to remove, it is besides the blocked user and staff.