You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you for today?

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

ASSISTANT: I am here to help you in changing your reservation.

USER: Thank you.

ASSISTANT: Can you please provide your name for checking the reservation status?

USER: Sure, my name is Donna Garcia.

ASSISTANT: Please wait for sometime to check for the reservation status.

USER: Sure, I will wait.

ASSISTANT: Sorry to say this Donna Garcia, there is no reservation found under your name to change your reservation.

USER: Ok, no problem. Anyways, thank you for your service.

ASSISTANT: You are welcome, thank you for opting our service. Have a safe journey.