Optional Model in Controller/View

I would need some help implementing an optional model in my view. Basically, I have a modelsLocks that is required in the Update action, but not the Create action.

I create it properly in the Update action and my view works just fine, but in my Create, it doesn’t like

if( !$model->isNewRecord && !empty($modelsLocks) ){
    if( $modelsLocks->UserId != $('#CurUsr').val() ){
        alert("This booking is currently locked by another user and connot be edit at this time.");

Complaining that ‘Undefined variable: modelsLocks’

It seems to process the if( $modelsLocks->UserId != $(’#CurUsr’).val() ){ line even though it is a NewRecord … so obviously it will err, but how can I get around this?

Where you are creating object $modelsLocks ?