Can I reuse my email after deleting account with that email address?

I am creating a family group and I have no idea what the master password is for one of the family users is. Can I delete the account and then reuse the same email to re-create the account at a later date/time?

Take a look here:

From my understanding they describe exactly your scenario.

And a few lines above of that they mention this:

If you’re locked out of your Vault and deleting your account so that you can create a new one, Contact Us and we can help transfer your subcription to the new account.

This might come in handy if you start running out of the 6 available accounts of your family plan.