What is the best way to change an article, without avoid penalty for duplicate content in order to submit it to a number of online directories?
Well you could obviously change around the sentence structure and use synonyms. Did you mean automatically? Because most spinners are still really unreliable if you want readable content.
PM me the text you want changing and I'll show you free what a state-of-the art automatic solution can do.
problem with translating back and forward is (as caffeinated content users found out) the result tends to trip the search engines anti-markov filters, so it's pretty much useless for serps processes. It's the translation BACK that causes the trouble - the result isn't within the statistical bell curve of 'normal' english, apparently.