You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: Could you please help me to change an existing reservation as my plan to meet my grand parents got postponed due to my heath issues?

ASSISTANT: Ok, could I have your name please?

USER: I am Kathleen Allen.

ASSISTANT: Ok, please allow me a moment.

USER: sure.

ASSISTANT: Sorry, there is no reservation with your name in our portal to make changes further.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: You are welcome, have a great day.