I just dropped a BF when my two went to one nap. For DS1 that was at 12mo and DS2 it was 15mo. Since they were no longer having a nap they didn't miss the feed that would normally have come after it (or actually before in DS2's case). I replaced it with solid food not cows milk. Cows milk we offered in my sippy cup with solid food. Cows milk is really just a drink rather than the food breast milk is.
With DS1 we dropped the middle feed (so from 3 feeds down to 2) a few months later just by distracting him when he got up from his nap instead of offering a BF.
With DS2 he stayed on 3 feeds for quite a few months more until 23mo and then we dropped the morning WU BF by having DH take him down for breakfast. We kept the midday and BT feed until we weaned him completely at 26mo with very gentle encouragement.
If you want to drop to 2 now you certainly can but there is no need to if you are happy to carry on until there is a more natural reduction in the feeds.
You may be interested in joining our
Re: Extended Nursing Support Thread Part 5 for those nursing LOs over 12mo.