If I have created a form and I chose "single choice", how do I switch it to "multiple choice" without re-doing the whole thing

need to modify "satisfactorily Performed/Demonstrated...." and "cartridges-demonstrates..."

You can't switch the field type directly. You will have to add a Multiple Choice field first then copy and paste the options from the Single Choice field and paste it into the Multiple Choice options. You can delete the Single Choice field afterward.