How can I ask the teacher for leave without notice?

If you can't get the notice, you can ask the teacher for leave by text message or phone.

If you have the teacher's mobile phone number, you can try to send a text message to the teacher or call the teacher directly to communicate. Explain your situation politely in text messages or phone calls and ask for leave. If the teacher can't answer the phone, you can leave a message to explain the situation.