Apologies if this question duplicates something in the archives - I
can't seem to find much of anything that suggests how to properly do
this, though what I've found suggests that it's possible.

We have a user who created a site for creating documents - he now
wants to change the URL of the site (say, /sites/blah to
/sites/blah_old) and use the original URL (/sites/blah) for other
work. Is there a good way to do this, either on the user or admin
side?