You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Betty Thomas.

ASSISTANT: How may I support you today?

USER: I want to change an exesting reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Ok, please wait a moment I will check the reservation list.

USER: Ok.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation found on this name.

USER: No issue.I will choose other alternative.

ASSISTANT: Thanks for choosing us.

USER: Thank you for the information.