I recently purchased a Native Instruments Komplete Audio 6 interface. It sounds great but I have run into a problem. After recording a half a dozen audio tracks, I want to mix them down to a single stereo track but I can find no way to route the output from those six tracks to the new stereo track. After reading a bit on line, I have come to the conclusion that it may not be possible to do that. Also, based on what I've read, that sort of routing is easy to accomplish with the mixer software included with the Sapphire 6i6. If any one has had experience with either of these units, I would be most grateful for your help. 

Hi Ruckman,
 
Sounds like you might be new to the home recording environment.  No worries...we've all been there and continue to learn as we go.  
 
As far as interfaces go - they all behave the same (give or take).  Mixing down to a stereo track actually takes place within Sonar and not your interface.  If you have recorded your six tracks, you should have those routed (within Sonar) to either separate stereo busses or ultimately, the stereo master buss.  Then you simply choose to export those tracks (from the file menu) as a single stereo audio file whether it be WAV, MP3, etc.  
 
Hope that helps clear things up a bit.

Hi. If you want bounce to a new track (in the project), select the tracks you want, click on tracks and choose bounce to tracks.

All the best.

Thank you for the advice. No, I am not new to recording. I have been using Cakewalk software since version 2 so I know my way around the software, despite what my query may otherwise indicate!! I am, however, new to recording on a laptop with an audio interface.
 
Neither bouncing down or creating stereo buses works, unfortunately. For example, I route several audio tracks to a new stereo bus and see that the signal is being received into the new bus. But, when recording onto a new audio track feeding just the contents on the new bus into the track, it plays back but it does not record. I have tried all variations of routing to and from the bus with no luck. I still think it may be a limitation with the NI Komplete Audio 6. I watched a YouTube video with someone using the loopback facility on the software that comes with the Sapphire interfaces and it did exactly what it is I am trying to do.     

Ruckman65
After recording a half a dozen audio tracks, I want to mix them down to a single stereo track but I can find no way to route the output from those six tracks to the new stereo track.

Two ways..
 
If the 6 tracks represent the entirety of your project, make sure they're routed to the Master bus (they should be by default) then Export the audio using Master as the source.
This creates a stereo file of your project, exactly as your heard it through the Master bus.
 
or  If you simply wish to submix those tracks and re-use the submixed file..  (maybe as a stem to import to a different DAW) you could route them to a new stereo bus then Export with the new bus as source, then drag the resulting file into a new track or DAW.

Hello Karyn. That's exactly how I used to do it when I was running Sonar on my PC. Unfortunately, I cannot get that to work with my laptop and the audio interface. All tracks are routed to the Master bus but when they are exported to audio, the track is blank. 

It's nothing to do with your interface, I assure you.  If the track is blank then you're probably  not selecting the time range to export correctly...
 
Before you start the export process, use (I think) ctrl-A to select all, then do the export.
 
You can create exports that contain just selected tracks, or a small portion of the project, depending on what you have selected in the project screen.  To export everything,  you need to select everything (or NOTHING and it will assume you want everything...)

Yes, ctrl + a will select everything.