You can change workload template settings at any time, even if the template has been used to create workloads. The only restriction is that you cannot specify a different VM template if the workload template is in use by a requested or deployed workload.
Changing a workload template has no immediate effect on deployed workloads. However, if a change is requested for a deployed workload, the workload settings are validated against the new workload template settings. This might require the Business Service Owner to change settings that he or she did not plan to change. For example, suppose that you create a workload template that allocates 4 CPUs. A Business Service Owner creates a workload (with 4 CPUs) from the workload template. You then change the workload template’s CPU allocation from 4 to 2. After the change, the Business Service Owner requests a change to the workload’s number of disks. When creating the change request, the Business Service Owner must also change the CPUs from 4 to 2 because 4 CPUs are no longer supported by the new workload template.