J.P.
It is really more difficult than just "skipping" a nap. They slowly move the morning nap later and later. My son dropped his PM nap at 13 months. We have increasingly pushed his AM nap later and later. It has taken us 6 months to go from 9:30 AM nap to an 11:30 nap time. It is a process, not an elimination. If you are determined to do it then just push it 1/2 hour every few weeks until it reaches 12/12:30.