This has been possible since 1.2 came out (as of now the most recent version is 1.21).
If you load your scene in Hosted mode and click the "save" button you should notice a line that says "SAVE HOSTED TO STANDALONE". Click the little circle next to this. Now the scene location selection will show your Standalone scenes (instead of Hosted scenes) — choose what slot you want to save your scene to and then click save. Your Hosted scene is now in Standalone mode.
All of your device/routes in the scene should automatically be changed to SSCOM Port 1 (you should double-check this though) so there's no need to change anything. You should also note that some sources aren't available in Standalone mode, so any modlines with those sources will no longer be functioning. There is also a limit of 48 total modlines per scene in Standalone mode, so if you have a scene with a lot of stuff going on you may hit this limit and will not be able to save to Standalone mode (a window will pop up and alert you when trying to save if this is the case).
2, 3, 5, 13, 89, 233, 1597, 28657, 514229, 433494437, 2971215073