Answer
Your number of employees may increase over time. If you need to increase your allowed employees, you can upgrade your current subscription (monthly or annual) to a higher level at any point. Alternatively, if you're near the end of your subscription period, you may choose to simply renew at a higher level instead.
To upgrade or renew your subscription, log in to your account and click View/Renew/Upgrade Subscriptions >>. Highlight the subscription you wish to modify, then click either Upgrade or Renew within the same screen.
When upgrading, a new subscription term (monthly or annual, depending on your original subscription) begins from the current date. The upgrade cost is calculated as the full price of the new level, minus the unused value of your existing subscription.
Example:
If you’re halfway through a small annual subscription ($249/year) and need to move to a medium subscription ($449/year), you would pay $324.50 — that is, $449 minus $124.50 (the remaining half of $249).