The database principal owns a schema in the database, and cannot be dropped.I tried out browsing the property of the user and removing the assigned scheme from the lists. It was somehow unsucessful. So I decided to go search for the solution and stumbled at doing it the most powerful way - through command.
Here goes the solution - Revoke the database schema assigned to the user and assign it back to the default db object.
ALTER AUTHORIZATION ON SCHEMA :: my_user_name to db_owner
If you want to assign the schema to another user, here is how you accomplish it.
ALTER AUTHORIZATION ON SCHEMA :: my_schema_name to my_user_name
Cheers!