Adobe Audition

As Steve says, we're short of information but I'm going to take a guess that, however you recorded your voices, you did them to a stereo track with one microphone on the right and the other on the left.

If you think you might have done this, there are various things you can do.

The simplest (but least flexible) is to just go to Edit/Convert Sample Type and, in the various options, select that you want a mono track.  However, I probably wouldn't do this.  Sometimes you want to apply different processing/effects to the different voices and you also need to be in stereo if you ever want to burn to a CD.

The method I'd chose would be to right click on the stereo track and select the "Extract channels to mono files" option.  This will give you two separate mono files.  Next, go to File/New/Multitrack session and create a session for editing your recordings.  Once you've done this, drag the two individual tracks into the session on, say, tracks 1 and 2.

Once you're set up this way you can control the relative levels of each voice separately, add different EQ to each track if you want, and so on.

You can also use the pan control (either with the knob in the controls at the left hand end of each track or with the "Pan envelope"--the blue line down the centre of each track) to put the voices where you want them.  This can be having them both in the centre or you can put each track just slightly off centre so both voices come from both speakers but there's still some spatial information.  Depending on what you're doing with your final product this can work well sometimes.

Finally, once you're done, use File/Export/Multitrack Session to convert you two tracks to a final product.

After all this typing, I hope I've guess your problem properly!