You can edit the hosting package of your account.
Or, if you have root access, you can edit the hosting packages of any user.
Follow these steps:
1. Log in to your WHM Account.
2. Go to Packages >> Edit a Package or type Edit a Package in the menu filter box.
The option will appear. Click on it.
3. Select the package you want to edit.
4. Under Edit a Package, you can modify resources like disk space, bandwidth, etc.
5. Scroll down, and click on Save Changes.
And that's all.
