IF Formula analysis on single cell

[Harwardj]

I have a string of data of about 1,000 lines eg

Yes Yes
No No
Other Formula
"" ""

if the cell = either Yes or No I want it to return the value Yes or No, otherwise I want to return a Formula I have set up. I can olny get the if function to work on a single function.

I want the function to look like:

if(a1="Yes"or"No","Yes"or"No",Formula).

Thanks