1- Login to your VPS panel via this link.
2- If you have more than 1 server select your desired server otherwise goto step 3.
3- In this page select Root/Admin Password tab.
4- And then click Change button to perform reset password.
5- To confirm reset password click Yes.
6- After that please wait a moment to perform reset password and to be displayed.
Copy password and select OK to close this window.
*Note that when you change the password, the server will reset.