That is already in place but during outage if a customer calls then business want the call center team to give them a proper reply.
The support team will need access CRM and ECC in backend to do that.
During maintenance period the call center team will not create or save any record. ONlY display function is needed.
Why SAP systems are required as we have customer with all the details like last bill record and various info that will come from SAP to call center team.