Is it possible to delete my QB Online Accountant subscription and start again?

You can open a new blank QBO Accountant account for free. No subscription.

https://quickbooks.grsm.io/UK

Hello Kyle-kmbookkeeping, 

Welcome to the Community page, 

So it is not possible to delete an accountants account. It would be a case of having to take out a new accountants account with a different email address to start again.