I am trying to update my EIN, but receive the following message: An application error has occurred while processing your request : -70012. What does this mean?

I'd like to welcome you to QuickBooks Community, rachel43.

One of the most possible reasons why you encountered this error is because your electronic services is active. We have to turn it off first, edit the EIN, then resubmit. You can follow these steps:

A. Turn off the E-File and Pay feature

1. Go to the Gear icon, select Payroll Settings.
2. Click E-file and e-pay, then select Manually with paper coupons.
3. Select Next.

B. Update EIN

1. Select Payroll Settings from the Gear icon.
2. Under Taxes, select Federal Taxes.
3. Enter the correct EIN, and select OK.

C. Re-enroll in electronic services

1. Go to again to the Payroll Settings.
2. Select E-file and e-pay, then E-pay and e-file (recommended).
3. Click Next. E-sign the authorization form.

If the purpose of the EIN update is an entity change, I suggest checking this article on how for insight into this process: Changing your business entity. 

I'll be here if you need anything else. Wishing you all the best!