Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
You did not explain why you need to change your personal account to a business account.
In any case, from the previous answers, you will know that they are separate accounts.
A personal account, for example peter @live.com, follows you as long as it is not deleted.
A business account, as a employee, is created by your employer IT within their Microsoft business tenant. It remains valid as long as your employment is valid and you are not removed by your employer from their system. If you work for multiple employers (for example a day job and a night job), you may be granted multiple business accounts.
Eg peter @contoso.com and peter @acme.com
If you intend to start your own business, and want to subscribe to Microsoft365 business basic for example, then you would be prompted, upon signup, to create an administrative business account in the form of (admin) @yourcompany.onmicrosoft.com, and later add a business domain in the form of peter @petercompany.com
So in conclusion. Your personal account stays your personal account.
A business account is either created by you as a business owner, or given to you as an employee of a firm.