Given the task definition and input, reply with output. You are given a conversation between two people. 'Person1:' and 'Person2:' are used to separate their respective dialogues. You are required to assign a label 'formal' if there is an absence of emotion and a presence of questions anywhere within the conversation. If such pattern is not found assign the label 'informal'.

Person1: Hello ? This is Mike here . May I have a word with Grace ?
Person2:She ' s not at her desk at the moment . Is there any message I can give her ?
Person1: Yes . Please tell her that tickets to Phantom of the Opera will be delivered in two days . My number is 6521684 0 , extension 236 .
Person2:Ok . I ' ll let her know as soon as possible .
Person1: Thanks a lot . Bye .
informal