1. Login to the Reseller control Panel. Switch to Classic Panel.
2. Click on Customers tab at the left side menu option (to find the customer account) and select the Customer account.
3. Click on Subscriptions tab.
4. List of Customer's subscription will be listed
5. Select the Dropbox Subscription with tick mark and click on Upgrade Resource Limits.
6. Here you will get a option to Increase the License, type the required units and click on Next to confirm the order.
7. However, here you can find the number of Maximum and Minimum Licenses for Dropbox business.
i) Minimum number of license is 3 Units (default).
ii) Maximum number of License is 1000 Units.