Do you mean "K1, sl yo purlwise, k1" ? (not "kl" )
This wouldn't make any sense If I were to start knitting this on stockinette st or garter st backgrounds. If a row below this one has a yo st and I need to slip it on my current row then this makes sense. Do you have a "yarn over" st on the previous row? If so, you can do "K1, slip the next st (which is a yarn over st) onto a needle as if you to purl. You don't have to do anything else to the slip st, then just knit the next st.
I hope this helps and thank you for visiting. Have a great day!