Today, I asked the tour guide for leave by SMS, and then the tour guide sent me a sentence. What do you mean by informing me?

Your tour guide may have some misunderstandings about the usage of the word "notice". In the context of asking for leave, "notice" usually refers to informing or transmitting information to the other party to let the other party know your plan or situation. Your tour guide may think that your message is a little blunt, like a notice rather than a request. You can try to resend a short message in a more polite and humble tone, clearly express your leave, and explain the reason and time of leave. For example, you can say, "Tour guide, I am XX, and my major is XX. Because of some urgent personal affairs, I plan to take a day off in XX. I have arranged my work to ensure that my absence will not affect the team or the course. If you need further information or approval, I will provide it at any time. Thank you for your understanding and support. "