You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you for today?

USER: I am planning to change my reservation to another destination, so can you help me to change my reservation?

ASSISTANT: I am glad to help you with your flight ticket changing. On whose name to have done your reservation?

USER: Sure, the reservation is on the name of Karen Martin.

ASSISTANT: Ok, please let me check the reservation status under your name.

USER: Ok.

ASSISTANT: Yes, Karen I have found your reservation. Can you please provide me your modification airport codes?

USER: Sure, my new airport codes are EWR and SFO.

ASSISTANT: May I know your planned dates of your journey?

USER: Sure, my travelling dates will be 02/16 and 02/18.

ASSISTANT: Please wait for sometime, I will check the suitable flight as per your specifications.

USER: Ok.

ASSISTANT: Thanks for waiting Karen, there are no flights which travels on your planned dates of your journey.

USER: That's ok, thank you.

ASSISTANT: You are most welcome, thank you for reaching out here. Hope you have a nice ahead.