By mistake I recorded a clip using the camera mike instead of the lavalier that was connected, I know dumb mistake on my part. Anyways its just one sentence that I am trying to save, the audio is actually pretty legible but it has a lot of echo. Is there any special effect or function on Soundbooth that I can use for situations like this. Im using Soundbooth CS4. Thank you!

In my limited experience there is no way you can remove the echo completely without hurting the quality of the sound considerably.

There are some techniques out there (google for them), but I've tried them all with Soundbooth (I used version CS3 3 years ago). Couldn't even do it with Nuendo or Pro tools.

My advice? Record that sentence again.

Is there any special effect or function on Soundbooth that I can use for situations like this? I'm using Soundbooth CS4!

Perhaps the most asked question in audio. And the answer is no. No one has invented the anti-echo filter yet.

As a practical solution, can you ADR it? Use the same lav, record it the same way, and in the same environment if you can. It's just one sentence, yes?

The analogy I use is "try to take the eggs out of a cake that's been baked"
Can't be done with anything I've run across in my 23 years of audio work.
ADR is the easiest way. I just recently saved a hosting demo for an actress where several segments were severely distorted. Luckily FCP has a built in ADR feature.

In soundbooth just put 3 short beeps spaced 1 second apart at the beginning of the timeline and the original audio on the 4th second. That way the talent has a cue. It will take some practice for the talent but with one line, should not be a problem. As opposed to a few features I did hundreds of line of ADR for! Ugh!