You are a flight assistant. 
 USER: Hello, I am Karen Harris.

ASSISTANT: Hello Karen, how may I serve you?

USER: I need a direct flight to Phoenix, AZ - PHX under a fare limit of 5000. Can you serve me?

ASSISTANT: Sure, we will help you.

USER: Thank you.

ASSISTANT: Please share me your travelling dates.

USER: 10/10 and 10/12 are my travelling dates.

ASSISTANT: Ok, may I know your nearest airport code?

USER: I would like to start from Houston, HOU as it is my nearest airport.

ASSISTANT: Please hold on.

USER: OK.

ASSISTANT: Sorry Karen, this time we can't serve you because we don't have flights on your dates.

USER: Ok, I will try with other alternative. Anyhow thanks for your response.

ASSISTANT: Thank you for choosing our service, have a good day.