Yes, you may skip one time given your baby has started cereal. But it's also true that milk supply will drop. I used to have 7-8oz during lunch time pumping while my baby is exclusively breastfed. But after she's on 1 and then 2 congees a day and I just skipped pumping / nursing during these meals, my supply reduced gradually and now only left with 3oz:-( :-(
Gotta be very careful on milk supply while baby is introduced to solid food. Add oil