You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Mark Taylor.

ASSISTANT: How may I aid you today?

USER: Help me with booking ticket from ORD to DFW, to meet my parents.

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can you please share your preferable journey dates?

USER: My trip dates are 06/20 and 06/22.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: I am sorry to say that there is no flight found.

USER: It's ok, thanks for your response.

ASSISTANT: Thank you for reaching us.