TurboTaxIrene, I have already followed the steps you have mentioned & not once but at least 4 times. S-Corp comes back when I try to add K-1 for Partnership.

You want to keep the K-1P, right?

I'm sorry -- I know this is frustrating.

If you haven't entered anything in that S-Corp K-1 screen, let's back out and see if there is a K-1S in the Delete Forms screen.

1. While in your return, click on Tax Tools > Tools (in the black bar at the side of your screen). 
2. Under "Other helpful links" click on Delete a form. Click Delete next to the K-1 S and follow the onscreen instructions.
   
3. Also look in the state section and delete that K-1 as well.
4. Once you have finished deleting the desired form(s) click the Continue with My Return box (in the lower right of your screen).

Or Try deleting it this way.  Go to the K-1 interview section here
Federal
Wages and Income
Then scroll way down to Business Items
Schedules K-1, Q - Click the Start or Update button

If the first screen says "Do you want to review Schedule K-1?". You have to answer yes and then click Update by  the Schedule K-1 type (LLC, S corp, trust). The next screen is the Summary screen listing all of the K-1 entered for that type of entity.  You can review, edit or delete it there.