Changing email domain name and Azure single sign on process. Portal

[AlKamuda1]

I'm posting this here in the Portal group. Our company is in the beginning process of changing our company name which will affect our Office365 tenant login usernames.  For Portal we us single sign on so our current Office365 email login information is used in Portal.  Portal is listed in our Active Directory as an Enterprise Application.  When I did some testing in changing my user domain name in Office365 login default and tried to log into Portal  - Portal created a new user profile for me based on the domain change and in the doing so the new profile is a blank slate (no map, apps, licenses, view only) based on the new domain while keeping my existing account in tack. 

How do I avoid the new user profile being created? 

Is there a process to follow when changing an email domain name I should be using?   

Thanks 

[John_Spence]

Nice question! I have been giving this one some thought too if I ever switched from SAML to AD authentication.

[MelissaNorthey]

I'm out here almost a year later looking for similar information.  Our email addresses are changing from .org to .gov and our ArcGIS Online accounts are set up using SAML.  One guy tested this out last week and it did the same thing to him, he got a new account set up in ArcGIS Online when he tried to log in as a viewer with none of his content.  I don't see where I can change email addresses and really don't want to have to migrate all of the content and group ownerships for our 300-ish accounts.  Is there a way around this?  Something I can proactively put in place before they switch our primary email addresses?