I have done this using DOM, but I am not an expert on this subject. Anyway I'll try to help you. Can you please tell what exactly needs to be done in detail.
"Simplicity is the ultimate sophistication..." ~Leonardo da Vinci~
SCJP 1.4
SAX is just for parsing XML - you can't use it to change XML (unless you want to write code that recreates the complete XML file).
DOM can be used, as could any of the other XML object models (XOM, JDOM, dom4j). See e534 to e538 for examples of how to work with attributes in DOM. See this for how to obtain a DOM Document from an XML file in the first place.
With a little knowledge, a cast iron skillet is non-stick and lasts a lifetime.