I have been looking at the Attributes available in SCIM (in the Azure Portal) and I have noticed that I can add two further Attributes. ID (which you can add for both Users and Groups) and "urn:ietf:params:scim:schemas:extension:Adobe:2.0:User:emailAliases" which can be added to just users. I was wondering if there was any documentation on how these can be used further. I am guessing I could map the Azure Object ID to the ID field and use this as a matching preference and thus this would allow me to update a users email address without a new user getting provisioned. Also I was wondering if you can simply assign the Proxy Addresses Azure Attribute to the emailAliases or does it not work like that. I was looking at the online documentation but I cannot find any reference to these.
I believe that you are asking for help related to Azure portal but best thing I can share with you the Azure complete book to download that will give complete solution for your problem that you are looking.