First try DROP SCHEMA schema_name
If the schema contains objects, the DROP statement fails.
I was trying to transfer a scheme that existed on a user account that came over when a database moved. I needed to delete the user but was getting hung-up on the schema that came with it. The schema matched the user name.
I tried the solution at this Q&A as well as at How to transfer the ownership of the dbo schema in SQL Server 2012 & Change tables from one user to another Nothing was working. I could not figure out what the problem was, The errors were, something like "can't find" I was not sure what it could not find, the account or the schema, but it did not make sense. Both the old user, and new user existed, I had already transferred db_owner and everything else except the schema to the new account.
I used the quires at List schema name and owners in sql server 2012 and I could see that the old account still had the schema of the same name no matter what I did.
I went looking for a way to find exactly what the schema was attached to. When I discovered that DROP SCHEMA only drops if there are no objects.
The schema dropped, and I was able to delete the old user.