You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I am Brenda Clark, I want to change my existing reservation, due to some health issues, can you help me with that?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait for a while to check your name in the reservation list and know you the current status.

USER: Sure.

ASSISTANT: Thank you for your time. Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us. Hope to serve you again. Have a nice day.