baby no poo for 1 day.

Hi mummies. My baby is going 3months. And i just switched his formula to similac RS which is suitable for babies with frequent spit-up. After he drink really less spit up but he doesnt poo everyday. 1 day poop and 1 day no poo. Is it normal? Kindly advise. I'm quite worry as he usually everyday poo once a day. ?