The "Modify VirtualHost" form only allows you to add or remove the FCGI mode and/or the PHP version used by the FCGI mode.
If you want to modify the path of a VirtualHost, you have to do it directly in the httpd-vhosts.conf file without forgetting to do Right-Click -> Restart from zero so that it is taken into account.
---------------------------------------------------------------
Documentation Apache -
Documentation PHP -
Documentation MySQL -
Wampserver install files & addons