Adding words

How:
You may add words to your quote if they are enclosed in [square brackets].  This shows your reader that the words are yours, and are not found in your source text. 

Rule: It cannot change the meaning of the quote or in any way misrepresent the meaning of the author.

Reason: sometimes a quote would otherwise be unclear:
"Dr. Vorsich treated her [Sarah Woodruff] with 50ccs of Malformin twice a day" (Richards 99). 

Deleting words   

How: Words may be deleted from a quote by using the ellipses (three periods in a row).

Rule: It cannot change the meaning of the quote or in any way misrepresent the meaning of the author.

Reason: words may be deleted if:
XXX the quote would otherwise be too long
XXX the author was too wordy
XXX the author included comments that don't apply to your discussion.