I tried changing the home directory for the account in a passwd file or something
Somewhat unclear? Which file exactly? In case you use the virtual users scheme, the pure.passwd file do nothing unless you run a command that recreate the "database" from it. Try "pure-pw mkdb".
The /etc/passwd however could be edited on the fly and any change to it should be applied next time the user log in.
You should read the documentation about it, pureftpd is not very hard to manage. Try this pdf :
http://mirrors.ircam.fr/pub/pure-ftpd/doc/readme.pdf
