Yes, you can switch from any combined pill to any mini pill. For example, Femodene is a combined oral contraceptive pill and Cerelle is a mini pill (progesterone-only pill). If you want to switch from Femodene to Cerelle, you should start taking Cerelle on the day after you take your last Femodene tablet from the present pill pack. If you switch in this way, you will be immediately protected against pregnancy.