You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am Sandra Allen.

ASSISTANT: How can I oblige you today?

USER: Can you assist me changing the existing reservation? Because my holiday trip plan with my friends got postponed.

ASSISTANT: Sure, we are mirthful to assist you. Please, wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting there is no reservation found with your name in our reservation list.

USER: Ok, Thanks for the quick response.

ASSISTANT: Thank you for availing us.