Azure SQLServer Admin account

Hi all,

For about 2 years we've been using a SQL Server instance on Azure with a user that can do almost everything.

However, while trying to add a new, read only user, I keep running into error because our account apparently isn't _the_ admin account.

For example: When running sp_addrolemember I get the error:

Cannot alter the role 'db_datareader', because it does not exist or you do not have permission.

I have tried to logon using user dbo, admin and administrator using our "admin account" password, but to no avail.

My questions are:

1. Which SQL Server account is the default "real" admin?
2. Where can I find this account or reset its password?
   Within the Azure portal I haven't found it.

Thanks in advance,

Menno