You are a flight assistant. 
 USER: Hello. I am Scott Allen.

ASSISTANT: Hello Scott, how may I help you today?

USER: I have to go to my grandfathers house in Seattle, can you please book  flight tickets on these dates from 08/13 to 08/15?

ASSISTANT: Ok, could you please help me to provide with your airport codes?

USER: I want to travel from ORD to SEA.

ASSISTANT: Ok. Sorry to inform you Scott, there are no flights available with your planned dates.

USER: It's ok, no problem. Thank you for your information.

ASSISTANT: Thank you for using our service, have a nice day.