Welcome to the forum.
First, what version of PrE are you using, and then, on what OS version?
In general (specifics can come, with the above info), one would Share/Publish+Share (or Export in older versions) the Timeline as an intermediate Audio-only file. That would be Imported, or Opened in the audio-editor program.
In PrE 11, or 12, one would go to Publish+Share, and then Computer. There, they would scroll down the list, to Audio. Note: the scroll bars are not easy to see, but easy to miss. Look to the far right of the Panel. With Audio selected, choose PCM/WAV @ 48KHz 16-bit. That will get you the best file to edit further with your DAW. When that editing is complete, use PCM/WAV @ 48KHz 16-bit, then Import the resultant edited Audio file into the PrE Project, placing it on an empty Audio Track, say Audio 2, or 3. To maintain its position, I would place the CTI (Current Time Indicator) at exactly the point that you want that edited Audio file to be, perhaps at the start of the Timeline. Then, with Snap turned ON, the edited Audio file should snap to the CTI.
When it is in place, you can Delete the other Audio (that which you exported for additional editing), or just go to the Audio Mixer, and check Mute for any Tracks, that contain that original material.
Hope that helps, and if you can let us know a bit more, then someone can step you through any "gray areas," for your specific version.