Hi @Prabu Subramanian ,
NOTE: HLF 1.4.x was retired by the HLF community in April 2021 (here). HLF on AKS marketplace template retired on end of July, 2021. Please see the note here.
The HLF on AKS marketplace template (having HLF 1.4.8) allows you to have the complete access to the cluster and the HLF node deployments. With this, you can utilize peer and fabric-ca CLI (binaries from HLF) to execute commands to issue new admin certificates using the deployed Fabric CA in the network and replace the same in a fault-tolerant way in the active channels (including the system channel).
Currently, we do not have any automation script to achieve this. However, you can reach out to the HLF community for more help.