Yes. You will be required to take the CPU out of Safety Mode and place it in "Maintenance Mode" to implement the logic changes. Upon completing the changes perform an "Auto-Transfer" using %SW60 in the Primary which will copy the changes to the Standby. Place the Primary back into Safety Mode prior to disconnecting and the Standby will follow.
Legacy KB System (APS) Data: RESL204692 V1.0, Originally authored by TVe on 03/02/2011, Last Edited by TVe on 03/02/2011
Related ranges: Modicon Quantum