A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Don't paraphrase too closely
Drafting your report
Part I. Research and writing: from planning to production

You paraphrase appropriately when you represent an idea in your own words more clearly or pointedly than the source does. But readers will think that you cross the line from fair paraphrase to plagiarism if they can match your words and phrasing with those of your source. For example, these next sentences plagiarize the two sentences you just read:

Booth, Colomb, and Williams claim that appropriate paraphrase is the use of one's own words to represent an idea to make a passage from a source clearer or more pointed. Readers can accuse a student of plagiarism, however, if his paraphrase is so similar to its source that someone can match words and phrases in the sentence and those in that source.

This next paraphrase borders on plagiarism:

Appropriate paraphrase rewrites a passage from a source into one's own words to make it clearer or more pointed. Readers think plagiarism occurs when a source is paraphrased so closely that they see parallels between words and phrases. (Booth, Colomb, and Williams, 2007).

This paraphrase does not plagiarize:

According to Booth, Colomb, and Williams (2007), paraphrase is the use of your own words to represent the ideas of another more clearly. It becomes plagiarism when readers see a word-for-word similarity between a paraphrase and a source.

To avoid seeming to plagiarize by paraphrase, don't read your source as you paraphrase it. Read the passage, look away, think about it for a moment; then still looking away, paraphrase it in your own words. Then check whether you can run your finger along your sentence and find the same ideas in the same order in your source. If you can, so can your readers. Try again.