Drop User Failed - User has granted one or more permission(s). - Part 2

Once again, I ran into the same issue as my previous post on a different server. Trying to drop a user, but not able to because "User has granted one or more permission(s)."

previous post:
http://becomingexceptional.blogspot.com/2012/04/drop-user-failed-user-has-granted-one.html

This time around though, there was one caveat, the endpoint was in use. I ran the same steps to determine what the endpoint was and what it was named.

So I had to change endpoint ownership to our SQL service account. But how to do it? I googled alter endpoint owner and found the following technet article:
http://technet.microsoft.com/en-us/library/ms187359.aspx

ALTER AUTHORIZATION ON ENDPOINT::Mirroring TO 'domain\svcaccount';
GO

I ran it, and I was now able to successfully delete the user.