Removing echo is extremely hard because the processor needs to understand which components of the sound are the echo and which are original, dry signal. There are, however, some techniques that can help a lot. A dynamic noise reducer that fades out the signal below a threshold might do the trick for you. Even simpler, an auto mute that cuts out the sound below that threshold might work.
As it just so happens… NewBlue has an audio clean up suite that includes these two tools as well as other techniques including powerful FFT based noise reduction. https://www.newbluefx.com/scrubbers.html
You can download the trial and test the different tools and see if one does it for you. If Auto Mute is your answer, you are in luck: Each of our VST collections includes one free tool, and Auto Mute is the freebie in the Scrubbers collection.
Good luck!
Todor Fay
NewBlue, Inc.