This article explains how to reset email account passwords in cPanel. If you have the Enhanced Email product, please refer to the link here.
2) Select the link "Email Accounts".
3) Select the link, "Password" for the appropriate email account.
4) Enter and confirm the new password in the appropriate text boxes. You can also push the "Password Generator" button to randomly create a secure password.
5) Push the button "Change Password" to store the new password.