When you first log-in to the poker software you are given the opportunity to create the nickname of your choice.  Unfortunately, this cannot be changed.

Note:  The 'nickname' that you see in the My Account area of our website is not the same as your poker nickname.  It is your unique public name that will be displayed within the multi-player casino games when using community features such as chat.  At the moment, multiplayer casino games are not available.