A true perm is permanent, so no, you cannot toggle between the two. A perm, once in the hair, needs to grow out of it. The most versatile solution? Use your perm rods like a roller set (like Bradley Copper’s character in American Hustle). Start with a strong holding gel all throughout your hair like Phyto Wet Gel. Roll your hair around the rods while it is very wet and allow it to dry completely before taking the rods out.
The rest of the time let your natural hair do what it does.