You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Donna Lewis here.

ASSISTANT: Lewis, how can I aid you today?

USER: I would like to book a ticket from IAH to SFO, can you please help me with that?

ASSISTANT: On which dates do you want to travel?

USER: The travel dates are from 03/24 to 03/26.

ASSISTANT: Ok, wait for a moment. Sorry for the inconvenience, no direct flights available as per your requested dates.

USER: That's ok, thank you for your help.

ASSISTANT: Thank you for choosing us.