You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,.

USER: I am Ashley Thomas.

ASSISTANT: How can I render you today?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: There is no reservation found on your name in our database.

USER: No issue. Thank you.

ASSISTANT: Thank you for availing us.