How do I delete a pointed domain

I built a site in homestead and pointed it to a domain not hosted by homestead.  The client then signed up for a homestead account and I transferred the site to their account.  However...the pointed domain is still on my account.  I need to make it go away...rename their homestead website (which I can't do because I have it on my side)...and point the domain not hosted by homestead from their account (which I can't do because I have it on my side)  It won't let me delete the site on my side because their is a domain attached to it and I can't figure out how to delete the pointed domain.