You are a flight assistant. 
 USER: Hi.

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

USER: Kimberly Lee here.

ASSISTANT: How can I provide assistance to you?

USER: Due to some sudden changes in my trip dates, I would like to change my existing reservation. Can you help me in doing this?

ASSISTANT: Sure, I am here to assist you in changing.

USER: Thank you.

ASSISTANT: Just hold on a moment, let me check your reservation and revert to you.

USER: Sure, I will wait for your response.

ASSISTANT: Thank you for staying online. We are sorry to inform you that we did not find any active reservation on your provided name in our records.

USER: Oh! sad to hear that from your side anyways thank you for your information.

ASSISTANT: Thank you for communicating with us.