You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Jack Lewis here. Can you please help me in changing my existing reservation?

ASSISTANT: Sure, please be on hold.

USER: Ok.

ASSISTANT: Thank you for your time, we found a reservation in your name. Can I have your airport codes?

USER: My airport codes are from LAX to PHL.

ASSISTANT: Help me with the trip dates?

USER: My trip dates are Aug 21st and Aug 23rd.

ASSISTANT: Do you have any specifications?

USER: I need a flight with single connection.

ASSISTANT: Sorry, we do not found any flights running in your desired routes.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for reaching us.