If you have blocked someone else and want to use a dial-pad code to remove them from your restricted list, use these standard landline and carrier codes:
There is no single "secret code" that works across all devices to unblock a standard contact, as unblocking is typically handled through your phone's software settings. However, specific codes exist for carrier-level services like and Landline call rejection . Service Codes for Unblocking code for unblocking phone number