From the dashboard click the 'User information' link on the 'MY STUFF' tile or navigate to User admin using the left side navigation bar of AIR-INSITE.  You'll end up here...

On the USER INFORMATION box (right side) there are two icons 'USER INFO' which is the default view and 'EDIT USER INFO'.  To edit the user info, go ahead and click the respective icon. Your now able to edit as required (see below).  Once complete, don't forget to save your changes using the 'Save user info changes' icon that displays whilst your in EDIT mode... 

That's it!