How to change my membership to a single user account?

To switch from the Microsoft 365 Family subscription to the Microsoft 365 Personal subscription, that is switching to a version with fewer features, the process is explained on the link below.

https://support.microsoft.com/en-us/office/switch-between-microsoft-365-subscriptions-3fcc1efc-2722-427f-8efa-db94b9b0a36b

Basically, you need to first cancel the Microsoft 365 subscription, then sign up to a new subscription for Microsoft 365 Personal.

https://support.microsoft.com/en-us/office/cancel-a-microsoft-365-subscription-46e2634c-c64b-4c65-94b9-2cc9c960e91b

Then, provided you use the exact same Microsoft account for the new subscription, you will still have access to all your files and the same 1TB of OneDrive storage from the Family subscription.

To change from a multi‑user Microsoft 365 plan (such as Family) to a single‑user plan (such as Personal), switch to a subscription with fewer features. This is done by cancelling the current plan and then choosing the new one during the cancellation flow.

Follow these steps:

1. Go to the Subscriptions page at https://account.microsoft.com/services and sign in with the Microsoft account used for the current Microsoft 365 subscription.
2. Locate the existing Microsoft 365 subscription and select Manage.
3. Select Cancel subscription.
4. On the Cancel page, review the information shown. When switching to a plan with fewer features, select the new plan (for example, Microsoft 365 Personal) when it is offered as part of the cancellation options.
5. Follow the on‑screen instructions to complete the switch.

The existing subscription may continue until the current term ends; it will then automatically renew into the new, single‑user plan, and billing will move to that plan at renewal.

If the subscription was purchased through a third‑party billing partner (such as Apple App Store, Google Play, or a retail partner), subscription changes (including switching plans) must be managed through that partner’s support, accessed via Manage on the same Subscriptions page.

References:

• Switch between Microsoft 365 subscriptions