You can change your account information using Personal Profile -> 'Edit Profile' option from within the User CP. If you want to change your Password there is an extra Page (Change Password) for that in the User CP, where you can set a new Password.

Edit Profile Page

This page allows you to set a number of required and optional details, some of which will be displayed on your public profile. With the exception of your e-mail address, do not enter information that you do not wish to be publicly viewable.

About You

These are the Basic Information about you

Location

Here you can optionally enter the Place where you live

Home Page

Here you can optionally enter a Home page and/or a Blog.

Instant messaging services

Here you can optionally enter your messenger Ids of services such as MSN, YAHOO, AIM, ICQ, XMPP, SKYPE.

Time Zone

Here you can specify the Time Zone to adjust the board Time and Date to your local Time. And set if the Daylight Saving Time should be automatically adjusted.

Forum Settings

Here you change your E-mail Address.

And if the Administrator has enabled it you can change the Forum Language and the Theme of the Site.