Actually, supervisor engine redundancy is configured by default when a second supervisor engine is detected.
Cisco_c6509# show redundancy states
my state = 13 -ACTIVE
peer state = 4 -STANDBY COLD
Mode = Duplex
Unit = Primary
Unit ID = 1
Redundancy Mode (Operational) = RPR
Redundancy Mode (Configured) = RPR
Split Mode = Disabled
Manual Swact = Enabled
Communications = Up
client count = 4
client_notification_TMR = 30000 milliseconds
keep_alive TMR = 4000 milliseconds
keep_alive count = 1
keep_alive threshold = 7
RF debug mask = 0x0
Cisco_c6509(config)# redundancy
Cisco_c6509(config-red)# main-cpu
Cisco_c6509(config-r-mc)# auto-sync standard
Cisco_c6509(config-r-mc)# end
Cisco_c6509# copy running-config startup-config
Cisco_c6509# redundancy force-switchover <—- Force to change supervisor card active.