Dear Groucho1943,
Thank you for sharing your question with the Microsoft community.
I understand that you would like to switch your current Microsoft 365 Personal subscription to Office 2024 subscription, please be assured that I will try to describe it in detail for you.
1->Cancel subscription:
Usually, if you have previously purchased a product from Microsoft's official website or offline authorised shops, you can view the relevant product information in the subscription screen of your Microsoft account, where you can cancel your current Microsoft 365 Personal subscription by clicking on the link below and logging into your account and clicking on Products->Manage Cancellation (If you have previously purchased from a third party store, such as the Apple Store or Google Play, you may need to contact the third party's support staff to help you cancel): Microsoft account | Subscriptions
2->After cancellation, you can get the relevant refund, which is important to note at the time of refund: How to get a refund on a Microsoft subscription - Microsoft Support

3->You can then purchase Office Home 2024 through the official website below, you can click on the link below to purchase:
4->After you subscribe you will be able to see the product information in your account subscription screen, you can directly click on the product -> click on install -> download and install.
You can also refer to this article for detailed installation steps: Download, install, or reinstall Microsoft 365, Office 2024, or Office 2021 on a PC or Mac - Microsoft Support
Hope it can help you.
If you have any progress or other questions, please feel free to contact us in the community.
Have a nice day😊.
Best regards
Isabella-MSFT | Microsoft Community Support Specialist