If for some reason you wish to change a password on an email account here is how you do so.
Note if you are on our UK server your site will be powered by Plesk not Cpanel please see the help with Plesk section of the knowledgebase.
Log into your hosting control panel
Simply go you https://yoursite.com/cpanel
In the search box type "Email" to filter the big list of functions then click "Email Accounts" You will now see a list of all your current email accounts.
Find the email address you wish to change the password for next to it there will be a button titled "Manage" Click that button
Enter the new password and click the "Update Email Settings" button at the bottom of the page
The password for that email account has now been changed