If your return has already been filed then you can take the following steps to get back into your return to complete the Form M1PR.

• Sign into TurboTax
• Go to My TurboTax > Tax Timeline > Some things you can do > Add a State (this allows you to get back into your original return)
• Once your return opens you can take the steps in the following answer. Once complete go to My Account > Print Center. You will need to print and mail in your Form M1PR and attach a copy of your CRP.

https://ttlc.intuit.com/replies/5790106