I filed my return but forgot my T5008/RL18. Need to amend but the forms are locked and I need to upgrade to Turbotax premier but option is missing from menu.

1. Status of my return is Completed since it has been filed already but I forgot to enter the T5008/RL18.

2. I go to my info and upgrade option is missing.
3. I go to Tslips, access T5008 and I get "This section requires an upgrade to TurboTax Premier on the next page."

4. I go to next page, "Enter my T5008" and I get "Locked items require an upgrade on the next page"

5. I go to next page, "Enter RL18" and I get a locked form with no options.

6. I click close RL18 and return.

... Back to square one.