As the cPanel account owner, you find it necessary to reset the password for some of your email accounts.
Using the 'User Manager' interface shows the list of email accounts available with a convenient 'Edit' link for each.
1. Log in to the cPanel interface as your cPanel account username.
2. Navigate to the following location:
cPanel: Home -> Preferences -> User Manager
3. Either search for the email address:
Or produce a list of all email accounts by selecting the "gear" icon, and choose 'Email'.