Sure. To switch from monthly to yearly, from your Premium Live account create a new Yearly subscription (using the same payment method). It will be listed as pending. Then cancel the previous monthly subscription. It will still give you access till the end of the billing period, at which point the new yearly subscription will kick in.
Switching from prepaid to recurring works similarly. Assuming your prepaid subscription is still in effect, purchase a new recurring subscription. It will remain in Pending state until the prepaid one expires, then it will become active.