You can try this PowerShell command:
$ouser.psbase.invoke("SetPassword",$pwd)
$ouser.psbase.CommitChanges()
The Set-AdUserPwd.ps1 script is seen here.
Set-AdUserPwd.ps1
Function Set-AdUserPwd
{
Param(
[string]$user,
[string]$pwd
) #end param
$oUser = [adsi]"LDAP://$user"
$ouser.psbase.invoke("SetPassword",$pwd)
$ouser.psbase.CommitChanges()
} # end function Set-AdUserPwd
Set-AdUserPwd -user "cn=bob,ou=HSG_TestOU,dc=nwtraders,dc=com" -pwd P@ssword1
Otherwise, You can try this self service password reset (
http://www.lepide.com/active-directory-self-service/) tool which provides facilitate to reset self active directory password and sent Email notification to users when their AD passwords expired.