Hi Asiye
Normally LiveCycle is configured to use LDAP authentication. In this case, LiveCycle is not really capable of changing the passwords - this must be done through the LDAP server (ie ActiveDirectory, etc).
If you're using Local domain, then passwords are stored in LiveCycle.
I'm sure there is an api for changing passwords, but I'm not sure what, or how you would find out about it.
If you'd like us to do some investigation for you, please email info-at-avoka.com.
Howard
http://www.avoka.com