Yes. You can upgrade or add users at any time. At renewal, customers can decrease the number of licenses and/or the number of licensed users to fit their business needs. For customers on monthly plans, renewals occur each month, and any requested reductions in license counts will take effect on the next month. For customers on annual plans, renewals occur on the specified renewal date (once per year), and any requested reductions in license counts will take effect at the next renewal date.