Click on Privacy in the left sidebar.

Click on View blocked contacts .

Tap Blocked contacts .

If you need a record of that conversation, check if the other person still has it and can screenshot it, or consider using Skype’s chat export feature before blocking in the future. Once you unblock someone, they are not automatically a "favorite" contact. You may need to search for their name again and select Add to Contacts to keep them easily accessible in your main list. Have you successfully unblocked someone? If you're still having trouble, try signing out of Skype completely, restarting your device, and signing back in before repeating the steps above.