Question from a newbie

[Aguilera, Luis]

Hi, 
I want to automatize change of the passphrase using gnupg from PHP.
But, I can't make it work from a command line in DOS mode.

I'm try to work out this with:
gpg --edit-key charlie passwd
and gpg turns the dialog mode and I've to type the actual passphrase, type
the new and re type the new one.

But I don't know how to pass the actual passphrase, enter the new  and re
enter this without the dialog with gpg.
Some body help me PLEASE!!

Luis Aguilera
Sorry about my poor language! (I'm speak spanish)