[xml] how to set or reset a namespace prefix?

["Krepis P." <krepisp gmail com>]

I need to either set or change a prefix for a namespace on an existing
document tree. There's plenty of ways to get the information on the
namespace, but I'm not sure how best to change the namespace prefix.
Do I just assign a new xmlChar * to xmlNsPtr->prefix, or do I need to
use a function for that (or do anything else along with it)?

Thanks all.