BIG-IP LTM - Moving connections between pools

Use a simple iRule that will select the pool that contains members for troubleshooting based on health-check or forced-failure manually.

when HTTP_REQUEST {
if { [active_members POOL_PRODUCTION < 1] } {
pool POOL_TSHOOT
}
}

If you intend to send traffic to a specific pool member based on existing pool member, you can probably utilize LB_SELECTED event and then a data group that has production pool member and the equivalent troubleshooting pool member and you can make a selection based on the mapping. Hope that gives some idea to move forward.