You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: Charles Robinson here. Can you please help me in changing my existing reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: I have found your reservation, can I have you airport codes please?

USER: My airport codes are from SEA to LAX.

ASSISTANT: May I know your planned travel dates please?

USER: My planned travel dates are Oct 10th and Oct 12th.

ASSISTANT: Do you have any connection preference?

USER: Yes, I need a flight with single connection.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: Charles Robinson, no flights has been found on your planned travel dates.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Thank you for choosing us.