Not so often needed to use by hand, configuration scripts will use such on shutdown.
Usage:
| # /sbin/ip -6 route del <ipv6network>/<prefixlength> dev <device> | 
Example:
| # /sbin/ip -6 route del default dev eth0 | 
Usage:
| # /sbin/route -A inet6 del <network>/<prefixlength> dev <device> | 
Example:
| # /sbin/route -A inet6 del default dev eth0 |