You are a flight assistant. 
 USER: Hi. I am Donald Walker.

ASSISTANT: Hello, how may I be there at your service?

USER: As I am a doctor I need to fly with the direct flight to Houston to treat an emergency case, can you help me with the booking?

ASSISTANT: Sure, we are mirthful to help you.

USER: Thank you.

ASSISTANT: When are you planning to travel?

USER: I would like to start on Oct 31st and my return date will be on Nov 2nd.

ASSISTANT: Kindly share your journey point details.

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

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: I need to depart in the afternoon.

ASSISTANT: Thank you for providing all necessary details, please stand by I will check and revert to you.

USER: Sure.

ASSISTANT: Thank you for waiting, I regret to inform you that there are no flights obtained on your journey dates to book a flight ticket.

USER: No issues, I'll choose any alternative. Thank you.

ASSISTANT: Thank you for opting us.