You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Charles Wilson here.

ASSISTANT: How may I help you today?

USER: I want to change my existing reservation due to my meeting place has been changed with my client. can you please help me with this?

ASSISTANT: Sure, we are here to aid you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no active reservation found on your name to change.

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

ASSISTANT: Thank you for choosing us.