Change Login Alias

Hey there, 

this is not really a technical PBI question so I'm not sure if this is the right place but I don't know if there is a better one:

I got a personal PBI Account with a custom Email of which I'm not the owner. My Microsoft 365 Account was created with this one so I can login to PBI Service. Now I would like to use another Email Address of which domain i do own. I put that as primary Alias in my Microsoft Account but the Power BI Service does not know it. What do I have to do to use the new Email as my PBI Credentials?

Thanks in advance!

Chris