C.C.
Hi E.. You are lucky...mine stopped taking two naps around 12 months. I just started pushing the morning nap back by 15 minutes every couple of days. When you get it to around 11:30 drop the second nap. My daughter did well with one nap around 12....she's now over 2 and she goes down closer to one, but 12 worked really well for awhile. It's all a learning process and you just have to take cues from your little one. Don't let him get too tired or he'll get wound up and take forever to fall asleep.
One nap at this time is tough because you can kiss ALL lunch dates goodbye, but at least you can now schedule some morning or late afternoon play dates/errands now. He'll probably start sleeping for 2.5 to 3 hours once you've transitioned to 1 nap and he'll go to bed at night easier too. Good luck!