How to Change the Microsoft Account Used on Your Windows Phone
If you have created a Microsoft account (Windows Live ID) that you no longer want to use on your Windows Phone, the operating system lets you change it for another account. However, this will mean losing all your apps, files, and settings so that you can start over and use a different account. In this guide, I will show how this works on your Windows Phone 7.5 and also explain the role of a Microsoft account in relation to Windows Phone.
Understanding the Role of Your Microsoft Account (Windows Live ID)
When using a Microsoft account on your Windows Phone, you also have an Xbox gamer tag created for it. You might not be aware of it, though. I wasn't, at first. Until I stumbled upon issues. While you can change the region for your Microsoft account at any time, you cannot change the region of your Xbox gamertag once it is set. Therefore, if you did not pay attention, you can end up in a weird situation: your Windows Live ID (Microsoft account) is set to use as a region a country in Europe (e.g. Romania) and the Xbox gamer tag associated with it is set to use as a region the US (for example). This can lead to problems when trying to purchase apps in the Windows Phone Marketplace. In order to access all the feature of Windows Phone and purchase apps in the Marketplace, the region must be the same for both or, if different, at least be set in compatible manner. For example, the Xbox gamertag cannot be created for all regions and countries. If, when creating it, you cannot select the same country as for your Microsoft account, you should choose a region close by, situated at least on the same continent. Only then you can avoid weird conflicts like the one mentioned above. However, if you do find yourself in an unpleasant situation, your only solution is to create a new Microsoft account and a new Xbox gamertag associated with it. Then, you can use them on your Windows Phone and switch from the old ID to the new one.
How to Reset Your Windows Phone
First, make sure you know the details of the new Microsoft account (Windows Live ID) you are about to use. Also, back up all the important data you have on your phone. You are about to lose it all. Another good thing to do is to make a list of all the apps that you are using so that you install and configure them again, once the new Microsoft account is used on your phone. Then, on your Windows Phone go to Settings -> System. There, scroll down to About.
Tap on About and scroll down to the Reset your phone button.
Tap on it and you are asked to confirm that you are OK to ahead and reset the phone and lose all your personal content. If you made the necessary backups, go ahead and tap Yes.
Your Windows Phone restarts and resets itself to the default apps, files, and settings.
When you start it again, you are welcomed by a wizard, taking you through its initial setup, just like when it was new and you started it for the first time.
Go through the wizard and provide the details of your new Windows Live ID (Microsoft account). Once the wizard is finished, you can install the apps you were using on the old ID and add any files and data that you backed up.
Unfortunately, the process of switching to a new Microsoft account is the equivalent of resetting your phone to its factory settings. That's why, before you go ahead with it, I recommend that you make a clear inventory of the apps, files, and content that you will need to manually back up and move over to the new Microsoft account.