Well the program doesn't know if the IRS has finished processing your return. Once Turbo Tax transmits your return and the IRS accepts it for processing then they are done with their part.
If you can't amend it might be because the program doesn't know it was accepted. For the Desktop program you have to check the filing status inside the program. Open your return and go up to menu item
File > Electronic Filing > Check Electronic Filing Status
Then save your return with the status. Go to File-Save.
