Officially there's no uninstaller of WHMReseller v5 - cPanel/WHM addon. That's why we're writing a tutorial for our clients who wants to remove WHMReseller from their cPanel server.
(Remove the whmreseller directory)
rm -rf /usr/local/cpanel/whostmgr/docroot/cgi/whmreseller
rm -rf /root/whmresellerbackup
(then look for and remove)
/usr/local/cpanel/whostmgr/docroot/cgi/whmreseller/wdmonitor >/dev/null 2>&1
/usr/local/cpanel/whostmgr/docroot/cgi/whmreseller/versionupdate >/dev/null 2>&1
(close and save)
(Remove hooks from WHM)
Login to WHM as root user and remove all WHMreseller Hooks under "WHM" >> "Manage Hooks". They usually reside down the bottom of the list. Simply look for hooks with "whmreseller" in the path.
That's it !!