Hello,
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If you want to update your game in Microsoft Store, you could create another submission in the Partner Center. Creating a new submission lets you make and publish whatever changes are needed, whether you're uploading new packages or just changing details such as price or category. To create a new submission for a published app, click Update next to the most recent submission shown on its Overview page.
For more information about app submission, please refer to this document.
Besides, for questions about publishing apps in the store, please ask in Publishing windows store app forum.
Thank you.