If you want to change a membership user’s password with the MembershipUser.ChangePassword method you need to know the user’s old password.

The following extension method defines a SetNewPassword method that enables you to reset the password without knowing the old one:

    public static class MembershipUserExtension
    {

        /// 

        /// Set a new password for the membership user
        /// 
        /// Membership user to extend
        /// New password
        /// True if the update was successful; otherwise, false.
        public static bool SetNewPassword(this MembershipUser membershipUser, string newPassword)
        {
            var generatedPassword = membershipUser.ResetPassword();
            return membershipUser.ChangePassword(generatedPassword, newPassword);
        }

    }

Please note that this method only works if the Membership Properties are defined as follows:

• RequiresQuestionAndAnswer is set to false.
• and EnablePasswordReset is set to true.