How do I delete the routed net after checking?

You can choose one of the following methods to delete routing on the selected net:

• Click the Undo button on the Edit toolbar. This option is best used when you have just completed routing and want to delete it immediately to update a setting or correct an error.
• Choose Delete Routing from the Command drop-down list in Wire Assistant and click All or Selected. 
• Click the Delete icon on the Virtuoso Space-based Router toolbar.