If one of your cPanel accounts reached the bandwidth limit set for him you can easily update the account’s bandwidth limit in WHM. To make this change you will either need to change the package assigned to the account or update the values set for the current package set.
To change the cPanel package for an account, just follow the instructions posted in this tutorial, just make sure that the new plan has a higher Bandwidth limit set then the current plan.
If you wish to keep the current plan and just update the bandwidth limit for it, please follow the steps in this article.
