The WHM/cPanel can be accessed without knowing the actual password if it satisfies a single condition i.e you must have shell access to the server. If you have the shell access through SSH Keypair or using VPS nodes on the server, you can simply access the WHM panel without knowing the actual root password of the server.
The steps to create a session to access the WHM panel for root or any reseller accounts without a password is detailed below.
whmapi1 is the command which could be executed via Linux Shell so as to accomplish this. WHM API 1 accesses the WHM interface’s features. You can make use of this API to administrate cPanel and WHM reseller accounts, perform server administration tasks and manage cPanel & WHM services.