That depends on what you mean by "changing"!You can change poses by clicking on your char inside a room which would open a menu where you can choose poses from. As a pup, you can only use the default pose set. In order to use custom poses you need to have the rank "delta" (blue name tag); which you will automatically be upgraded to one month after joining.You can already change the colours of your default poses, however, by clicking on the button with the 3 blue bars on the top right of the map (next to your name) and click the option "edit wolf/poses" in the menu that appears.