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

ASSISTANT: Hello, may I know how best I can help you today?

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

ASSISTANT: Sure, I am ravish to help you.

USER: Thank you.

ASSISTANT: When are you planning to travel?

USER: I would like to depart on Apr 28th and I will return within two days that is on Apr 30th.

ASSISTANT: Could you please share your exact airport codes?

USER: My source and destination airport codes are HOU and BOS.

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

USER: I want to depart and return in the evening.

ASSISTANT:  We are unable to provide flight in between your journey routes due to some technical up-gradation at destination airport.

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

ASSISTANT: Thank you for choosing us.