You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: John Roberts here. Could you please help in booking a flight from LAS to IAH.

ASSISTANT: Let me know your travel dates.

USER: My travel dates are as follows Apr 18 and Apr 20.

ASSISTANT: Is there any connection limit?

USER: I would like to travel by single connection flight.

ASSISTANT: Do you have any preference?

USER: No. Thank you for asking.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: No issue, thank you for the precious time.

ASSISTANT: Thank you.