How to disable unnecessary notifier

Question

So I'm trying to create some ride sharing app. So when user enters required info (form dest to dest date) if this kind of trip exist in database one should be redirected to the next screen but if any of the mandatory fields (from dest to dest trip date) are not equal to already created trip offers one should get a notifier that there are no offered trips for this destination at certain date and user should fill ride request form by clicking on create trip button. So when all parameters are ok new screen opens but notifier user is anyway notified that trip doesn't exist. Please see attached graph from my code.

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