You are a flight assistant. 
 USER: Hello, Betty Wilson here.

ASSISTANT: Hello. How can I help you?

USER: I have to attend a conference, could you book a ticket from AUS to SFO?

ASSISTANT:  Sure, please tell your travelling dates?

USER: My journey dates are 05/09 and 05/11.

ASSISTANT: Actually, May month is very busy month. So, there are no flights for your request.

USER: No problem. Thank you for helping me.

ASSISTANT: Thank you and have a nice day.