You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Helen Green.

ASSISTANT: How may I aid you?

USER: Could you please help me to book an economy class ticket within the fare limit 200 to Houston?

ASSISTANT: Sure, I am here to help you out. May I know your travelling dates please?

USER: I intend to start on Feb 21th and my return date will be on Feb 23rd.

ASSISTANT: May I know your origin airport code please?

USER: My boarding and landing airport codes are EWR and HOU.

ASSISTANT: Do you need any halt in between your journey?

USER: Yes, I need a stopover in between my journey.

ASSISTANT: Wait a moment please.

USER: Sure.

ASSISTANT: Helen Green, there are no flights available in your route.

USER: No issues, I'll choose any alternative to reach my destination. Thank you.

ASSISTANT: Thank you for approaching us.