From taking a quick glance at the similac page the pro- advance is non gmo and has added hmo to make it closer to breast milk whereas the advance formula doesn't
I think it is fine. Both are good formulas. Sometimes switching formula can cause some diarrhea or tummy gas but you can keep an eye out. Baby should be fine.
From what I can tell, the pro has HMO which is a prebiotic that makes it very close to breast milk. The advance doesn't have it. Other than that they appear to be the same.