Paraphrasing is not simply rearranging or rewording an original passage. Correct paraphrasing consists of:
Reading
the original passage,
Understanding
what the original author is saying,
Synthesizing
(putting together) the information,
Expressing
your understanding of these ideas in your own words and then
Citing
the original author.
Paraphrasing properly not only keeps you from plagiarizing, it helps you really learn and understand the original source material. It also can make you a more skilled writer.