Log in as the mail admin for your domain and click User Administrator from the drop down box in the upper right corner. In the User Administration box, select the email account from the drop down box and click on "Change Password." You will be asked to confirm the password.
For assistance logging in as the User Administrator, please go to http://www.webservio.net/support/imail/index.cfm. If you do not have your admin access information, please contact firstname.lastname@example.org.