NSString *username = @"[USERNAME]"
NSString *tempPassword = @"[PASSWORD]"
NSString *newPassword = @"[PASSWORD]"
NSDictionary *args = [NSDictionary dictionaryWithObjectsAndKeys:username, @"username", tempPassword, @"password", newPassword, @"new_password" nil];

[[StackMob stackmob] loginWithArguments:args andCallback:^(BOOL success, id result) {
    if (success) {
        // Login Succeeded
    } else {
        // Login Failed
    }
}];