You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your good name please?

USER: My name is Patricia Lewis.

ASSISTANT: How can I help you Patricia?

USER: My grandmother is sick and I am planning to visit her, could you book a ticket for me?

ASSISTANT: Sure, please provide your travelling details?

USER: My airport codes are AUS and OAK. My travel dates are 06/19 and 06/21. Price limit is 200.

ASSISTANT: Sorry, there are no flights on your requested dates.

USER: It's ok. Thank you for your help.

ASSISTANT: Thank you for reaching us.