You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I need a direct flight to reach Houston as my grandmother is hospitalized, so can you please book me a flight ticket on the name Joshua Johnson?

ASSISTANT: Sure, please share your planned travelling dates?

USER: I will go on 08/28 and return back on 08/30.

ASSISTANT: Please share your source and destination airport codes?

USER: My location points are from BOS to IAH.

ASSISTANT: I regret that there are no flights available with the given details.

USER: No issue, thank you.

ASSISTANT: Thank you for opting us.