You can change the email or password by clicking on the icon with the user's photo in the upper left corner and selecting "Profile". If you want to change mail to another employee, then you must have administrator rights. This can be done by selecting "Users" in the "Settings" menu item. To edit the user information, click on the user.
Is the user in more than one account?
Unfortunately, the administrator of the account can not change the user name and password. According to the logic of the system, when adding one user to several accounts, changing the name and password, it becomes possible only by the user in the profile settings.