Monalisa said: Suppose , I develop a totally different content changing most of the phrases and words, do I still need to cite the source?
If it's "totally different content", then how would "most of the phrases and words" of the (now unrelated) original article discussing some other (now unrelated) topic have any bearing? Why would one even want to "cite" an unrelated article as a "source"?
The illogic tends to lead one to think that perhaps someone's motives and plans are not entirely "above board".
Instead of trying to find out how many words in a row you can re-use (from your other thread on this topic) or how little or how much you "have" to change an author's original work to "get away with" using it, why not create your own material...?