I want to cancel and down grade my subscription with refund

The method to switch from the Microsoft 365 Family subscription to the Personal subscription is explained on this link.

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

Because you are switching to a version of Office with fewer features, you need to cancel your subscription using the steps on this link first, then take out a new subscription to the Microsoft 365 Personal version, if you are entitled to a refund, that may take 5 - 10 days to be credited to your account..

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

To cancel Microsoft 365 Family and move to Microsoft 365 Personal, and then check for a refund or price difference, follow these steps:

1. Go to the Services & subscriptions page for Microsoft 365:
   • https://account.microsoft.com/services/microsoft365
   • Sign in with the same Microsoft account that is currently using Microsoft 365 Family.
2. Cancel the current subscription:
   • Find the Microsoft 365 Family subscription.
   • Select Manage or Cancel subscription (it might appear as Upgrade or Cancel).
   • If instead of Manage/Cancel the page shows Turn on recurring billing, the subscription is already set to expire on the date shown and will not be charged again.
   • On the cancel page, review the Please review section and follow the prompts.
   • Confirm with I don't want my subscription to complete cancellation.
3. Check refund eligibility:
   • During the cancellation flow, the page will indicate whether the subscription is eligible for a refund based on Microsoft’s refund policy and, in some countries, prorated refund rules.
   • If eligible, follow the on‑screen instructions to request the refund. The refund (full or prorated) is handled as part of the cancellation process.
4. Purchase Microsoft 365 Personal:
   • After cancellation is complete (or scheduled to end), return to the Microsoft 365 services page and purchase Microsoft 365 Personal under the same account.
   • If a refund for the Family plan is granted, the charge for the new Personal plan will be separate; if only a partial/prorated refund is available, that will reflect the difference in unused time.

Important notes:

• If the subscription was purchased through Google Play or the Apple App Store, cancellation and any refund must be requested through their support, not through the Microsoft account portal.
• After cancelling Microsoft 365 Family, cloud storage reverts to the free quota (5 GB OneDrive + Outlook.com attachment storage and 15 GB Outlook.com mailbox). Anyone previously sharing the Family subscription will also lose the extra storage and benefits, so files and email may need to be backed up if over the free limit.

For more details on cancellation, storage impact, and refund eligibility, use the guidance in the referenced articles below.

References:

• How to get a refund on a Microsoft subscription
• Cancel a Microsoft 365 subscription
• Request refund - Microsoft Q&A
• I received an e-mail offering 365 Family Classic option but cannot switch - Microsoft Q&A
• How to unsubscribe microsoft 365 account? - Microsoft Q&A
• Can I speak to someone? -- Billing issues - Microsoft Q&A