i tried using the text function for the last part of the formula but
it didn't work

any ideas?

Maybe something like:
=TEXT(VLOOKUP(...),IF(VLOOKUP(...)1,"Mmm d, yyyy","0.00%"))
That is, the IF() test determines the format_text parameter of the TEXT() function, and the result is a text value.

If that doesn't meet the need, it'd help to see more edetail about what you're trying to achieve. Apparently, values <=1 should appear as a percentage, while others should appear as a date. Is there something more to it than that?