Understanding Plagiarism

Paraphrasing takes someone else's ideas, places them in your own words, and credits the original source by using a citation. 

Here is an example of a paraphrase from the writing center's guide to Using Outside Sources:

Original Text
Where European countries mete out time in spoonfulls, we give it out in buckets. Where they sentence for one or two, we give ten; where they give five, we give twenty.

Paraphrase
In addition, David Rothman points out that prison sentences are harsher in the 
U.S. than in European countries (28).

Summarizing also places someone else's ideas in your own words with a focus on the main points, and credits the source by using a citation. Since it only contains essential points, it is usually much shorter than the original source.

According to the F&M Writing Center's guide to Using Outside Sources:

"Whenever you incorporate into your paper an idea from an outside source—any idea that is not obviously common knowledge and was not originally your own—you must acknowledge the source of the idea. Acknowledge a source whether you summarize, paraphrase, or quote. Acknowledge a source whether it is an authoritative scholarly work or a peer you’ve consulted for advice. Take care never to leave unclear which words express your original thoughts and which words—no matter how significant or insignificant they seem—are derived from another source" (Writing Center, 19). 

Quotations mark a source’s exact words with quotation marks “” and credits the source by using a citation. 

If you need to make changes to any of the quoted material you must identify your changes. For specifics about this please see the writing center's guide to Using Outside Sources starting on page 15.

For example according to Using Outiside Sources "you may use brackets to change verb tense" (Writing Center, 16):

When he realizes that Addie is dying and acknowledges his 
mistakes, he determines to “[beg] the forgiveness of the man 
whom [he] betrayed” (Faulkner qtd. in NAAL 1598).