How to change the FTP user path in cPanel
By default cPanel does not allow you to change the FTP path for your main account or sub-accounts, after creating the domain. But you can easily change it from the FTP user configuration files. Each cPanel user has a file in /etc/proftpd (yes, even if you use pure-ftp)
# cat /etc/proftpd/user
As you can see, /etc/proftpd contains a file for each of the accounts on the server. Edit the file for the domain, and change the home directory.
After editing save the file and then restart your pure-ftpd service