Editing is a very important step before handling a translation. It consists in reading the target-language text carefully (the text resulting from the translation) with an eye on the source-language text (the original text) so as to eliminate any syntax, spelling, grammar or typographic mistakes. It also aims at improving stylistic quality and using the right terminology for a more coherent work.
You may also ask me to edit a text that has already been translated by others. My review of this text will be all the more relevant and objective as I will not have translated it myself.