I want to file amendment before completing my return

You do not "file an amendment" before you file your tax return.  Amending is a special process you only use if you already filed the return and the IRS processed it ---and you discover after filing it that you made a mistake or left out some information.   If you have not yet filed, do not click on the word "amend" anywhere.

You can make changes to the return before you file ----that is not the same thing as "amending."     What do you need to change?

You can only amend a return that has already been filed and completed. I'm not sure what your question is.

Please call TurboTax Customer service.  Here is a link:  Turbo Tax Customer Service