No, it's not possible to move returns between accounts.

its a year later... is there still no way to merge 2 accounts into one?

Hey intuit.  I'm here with the same question.  I can see that  1,274 other users have also been looking for this answer.  We want to merge accounts! PLEASE create a way for us to do this.

Unfortunately, it's still not possible to move returns between accounts or merge TurboTax accounts.

I have passed on your request to our product development team. Thank you for your input.