Changing System Admin in MDS database

So the consultant who created our MDS database has left but his account is still the system admin. I looked everywhere online on how to change the old admin and it suggested everywhere to do it through udpSecuritySetAdministrator  stored procedure but the problem for me is that I cannot find the udpSecuritySetAdministrator in the MDS database. I looked everywhere in the database but it simply does not exist and I even created a new MDS database and stored procedure still does not exist. Any suggestions? Thanks!