How do I modify the 2023 8453-FE for a fiscal year starting August 1, 2023 and ending July 31, 2024 as TurboTax Business will not allow me to modify to e-file?

You need to print out the form and manually change the dates. 

Then you scan that (manually altered) form and upload it into the program.

I again printed out the form, again manually changed the dates, and again scanned the manually altered form. I then went back into the TT Business program, deleted the previously uploaded form, and uploaded it the new form into the TT Business program.  It (apparently gremlins) then allowed me to e-file, showing successful!  Thanks