Managing personal Outlook.com account settings, security, and privacy
You'd need to update your profile settings directly through the Microsoft account dashboard by first signing in with your credentials. Once you are logged in, select the section labeled Your info from the top menu and look for the option to edit your country or region. From the dropdown list, select the United States, choose your state, and provide a valid U.S. billing and shipping address before saving your changes.
After updating your account online, adjust the regional settings on your devices to ensure everything syncs properly. On a Windows computer, you can do this by opening the settings menu, navigating to the time and language section, and switching your country or region to the United States. For an Xbox console, press the main Xbox button, open the profile and system settings, locate the language and location preferences, and change your location to the United States before restarting the console.
Before completing this transfer, there are several financial and subscription factors to keep in mind. Any funds remaining in your balance cannot be converted or transferred between regions, so you might want to spend your remaining Euros beforehand. Additionally, active subscriptions like Microsoft 365 might be locked to German billing, meaning you may need to cancel them and re-subscribe using a valid United States payment method once your account region has officially changed. Finally, keep in mind that Microsoft limits how frequently you can switch your region, often restricting changes to once every three months.
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hth
Marcin