Hi Claudie,
No, that is not possible. They are two different entities. You will need to make sure that you backup your data and e-mails if you want to migrate and then cancel your personal subscription.
You can then sign up (or run business simultaneously with your personal subscription).
Set up Microsoft 365 for business
https://learn.microsoft.com/en-us/microsoft-365/admin/setup/setup?view=o365-worldwide
If this is helpful please accept answer.