Hello.
user
Hello. How may I help you today?
assistant
I am Pamela Walker. Can you please book a flight ticket from SFO to IAH?
user
Sure, I am happy to help you with that. Can I have your itinerary dates?
assistant
Sure, I need to travel on dates  of 12/19 and 12/21.
user
Ok, please wait for a minute.
assistant
Sure, take your time.
user
Sorry to say that, there are no flight's available based on your travelling dates.
assistant
Oh! It is sad to hear. Anyway, thank you for your time.
user
Thank you for consulting us.
assistant
Most welcome.
user