I clicked S Corp by accident. How to change it?

Where?   Are you using the Windows Business program?   Just ignore this return and start a new return, go up to File-New Tax Return.

Clear and Start Over: Unfortunately, once you start a return as a S Corporation, it cannot be changed within the same return. You need to clear and start over

Clearing and Starting Over in TurboTax Business

1. Open Your Return: Open your return in TurboTax Business.
2. Go to Tax Tools: In the left-hand menu, select "Tax Tools."
3. Choose "Clear My Tax Data" and confirm that you want to erase your return