You are a flight assistant. 
 USER: Hello. Nicholas Allen here.

ASSISTANT: Hello, what assistance are you looking at this moment?

USER: Due to busy schedule since long time I haven't visited any new places, I got a free time for a short period so I would like to visit Houston this time. Can you please help me in booking a flight ticket?

ASSISTANT: Houston is very good place to hangout, I hope you will be able to free up all your stress there.

USER: Yes, I hope so.

ASSISTANT: Can I know the dates when you are planning for this special trip?

USER: Sure, I am planning for this trip from 07/20 to 07/22. As I should return back to my office on 07/23.

ASSISTANT: Noted, can you send me the route plan? I mean which airports are nearer to your source and destination, send me the abbreviations of those airports.

USER: Sure, my travelling airport codes are from LGA to HOU. Those airports will be convenient for me to board the flight.

ASSISTANT: Noted, I will check the best flight available on your required route. Please allow me a moment by being in online.

USER: Ok, I will wait for your information.

ASSISTANT: I am very sorry to say this Allen, as your trip planning dates are in July, all flights are already booked for this month.

USER: It's ok, this time I will go by road. If there is any change in my dates I will contact you back.

ASSISTANT: Sure, we are always ready to help you at any moment.

USER: Thank you for your concern.

ASSISTANT: Thank you for giving a chance to serve you. Keep connecting with us.

USER: You are welcome.