Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
There is no method provided to move purchased software or a Microsoft 365 subscription to another Microsoft account, that is locked to the Microsoft account used to initially activate it.
Because this forum is a user to user forum, no-one here has any account access, you will need to contact Microsoft Support directly to ask them to move that licence, try using this method to contact their support.
Go to this link: https://support.microsoft.com/contactus
Select Microsoft 365
Click 'Get Home Support'.
In the box provided, type billing.
Press Enter, then on the next page, scroll down and click 'Sign in to Contact Support'.
Navigate to Microsoft 365 and Office - Manage my Subscription.
Select the 'Chat with support agent in web browser' option