An application can show local information while disconnected and later exchange changes with a server. Synchronisation is the process of bringing those copies into an agreed state. A visible change does not always mean the server has saved it. Interfaces may distinguish pending, synced, and failed operations. If two devices edit the same record, the application needs a conflict policy. It might keep versions, ask the user, or apply a defined ordering rule. Different policies have different consequences. An offline reading page may work because its content was cached, while a new search still requires a network request. Signing into another account should not mix its pending changes with the previous account’s data. Reliable design makes these boundaries visible instead of presenting every local action as complete. Practice: Describe what should happen when a bookmark is changed offline and the account is then switched. List the status information a user would need.