You can use the clear redundancy history command to clear the high availability switchover history for the router.
clear redundancy history
host1# show redundancy history detail
system up time: 0 00:08:01
last cold start: 2004-07-26 10:44:25
last cold switchover: 2004-07-25 18:51:56
last warm switchover: 2004-07-25 20:58:57
activation statistics:
cold starts: 92
switchovers:
cold: 21
warm: 147
consecutive warm: 0
system
SRP activation time type slot uptime running release
------------------- ----------- ---- ---------- -------------------------
2004-07-26 10:44:25 cold-start 07 --- L-07-25-60b1mrg-e.rel
2004-07-25 20:58:57 warm-switch 06 0 00:15:08 L-07-25-60b1mrg-e.rel
2004-07-25 20:53:41 warm-switch 07 0 00:09:51 L-07-25-60b1mrg-e.rel
2004-07-25 20:44:43 cold-start 06 --- L-07-25-60b1mrg-e.rel
2004-07-25 19:32:01 cold-start 06 --- L-07-25-60b1mrg-d.rel
2004-07-25 18:58:01 warm-switch 06 0 00:12:01 L-07-25-60b1mrg-c.rel
2004-07-25 18:51:56 cold-switch 07 0 00:05:56 L-07-25-60b1mrg-c.rel
host1# clear redundancy history
host1# show redundancy history
system up time: 0 00:08:01
last cold start: 2004-07-26 10:44:25
last cold switchover: 2004-07-25 18:51:56
last warm switchover: 2004-07-25 20:58:57
activation statistics:
cold starts: 92
switchovers:
cold: 21
warm: 147
consecutive warm: 0
system
SRP activation time type slot uptime running release
------------------- ----------- ---- ---------- -------------------------