Yep, you just shorten one or both naps.
As they transition to 1 nap (getting longer A times), sleep does need to be cut here and there.
This didn't happen for us until much later but it got to a point where DD had to have 30 min. or less in the morning in order to take a good afternoon nap and be in bed at a decent hour.
I'd maybe cut off 30 min. of each nap....1.5 hours each and see if that helps any
With any routine change it does take a few days for their bodies to adjust so give it some time before looking for really great positive results.