You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you please help me with booking a flight ticket from IAH to DFW?

ASSISTANT: Sure, what are your travel dates?

USER: My travelling dates are from May 21-23.

ASSISTANT: Do you need any connections?

USER: I would be comfortable with single stop over.

ASSISTANT: Are there any other preferences?

USER: My depart has to be in evening.

ASSISTANT: May I know your name?

USER: Robert Thomas here.

ASSISTANT: Sorry, there is no flight found with your details.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.