You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you today?

USER: Actually, I want to change my existing reservation which is done recently due to some health issues, can you please help me?

ASSISTANT: Sure, may I know your name please?

USER: Sure, my name is Donna Jackson.

ASSISTANT: Please wait for a while.

USER: Sure, I will wait.

ASSISTANT: We have not found your reservation in our system.

USER: Ok, not an issue. Anyways, thank you for your service.

ASSISTANT: Thank you for reaching us.