Hi Krister,
I understand you’d like to change the payment period from monthly to yearly. However, we cannot change this directly. We suggest you purchase a new yearly subscription and then cancel the previous subscription.
The cancellation process differs based on the current subscription. Therefore, I’d like to collect the following information:
1. Which plan of Office 365 have you subscribed to, Small Business or Enterprise?
2. Are you using Office 365 pre-upgrade or after-upgrade? Please see Am I using Office 365 after the service upgrade?
Best Regards,
Bruce Zhou