
uhm...
You tryed to change it in this page?
http://www.pokemon-trainer.com/account/security because here it only ask you to write your old password and the new one

If you tryed to login and click on the "forgot password" you will receive 2 e-mails:
1. the first one that ask you to click on the link to generate a new password
2. the second one with the new generated password (something like this: iiKjK_T7 )
With this new password you have to login and after that you have to change it here
http://www.pokemon-trainer.com/account/security (remember to do this with the generated password

)
If you still can't change it, I can do it for you but it's better if you send me a private message (or a mail to
staff@pokemon-trainer.com ),
But it's always better if nobody but you know the password (so it's better if you send a 1 time only password and change it as soon as possibile

)