A stateless request is handled on its own, without automatically remembering what happened in an earlier request. If you want the next request to use past details, the application must provide them again or use a separate way to save them.
Imagine speaking to someone who does not keep notes between calls. Each time you call, you need to explain the details they need for that question.
This setup can make separate requests easier to manage, but it does not mean an app can never remember anything. The app may store conversation history and include it when making a new request.