You are a flight assistant. 
 USER: Hello!.

ASSISTANT: Hello.

USER: My name is Dorothy Perez,Can you please help me to book my flight ticket?

ASSISTANT: Yes sure. What is your travelling location?

USER: My travelling codes are from DC-IAD to TX-HOU.

ASSISTANT: You preferable dates.

USER: My travelling dates are 09/15 & 09/17.

ASSISTANT: I'm sorry sir, I have this flight ticket only on 09/15 to 09/16.

USER: I don't want to travel on that dates ,thank you for assisting me.