The primary email address associated with the Microsoft account I use on my Xbox and Windows Phone is one associated with an ISP. I also have an outlook.com alias associated with this account as well as my mobile phone number. I will be leaving my ISP in a few weeks and want to know whether or not I can still manage the account even if the primary email address is no longer active. E.g. will emails relating to this account be sent to the outlook.com alias as well as I will not be able to read or respond to emails sent to the ISP address?

If I need to rename the primary email address my understanding is I will not be able to use the existing alias, is that correct? Also, according to the information listed here I will have to factory reset my phone. Is that correct? The same page states that renaming isn't recommended so I'm hoping I will be able to manage the account using the existing outlook.com alias - I really don't want to reset my phone if it can be avoided.