Need to define timeshift to a timezone for past time which is already associated to an active contract.
CA Business Service Insight 8.35
Unfortunately, we cannot add a time shift for a timezone for past time if the timezone is in use by any contract. This is expected behavior as per the design. The same has been mentioned in the documentation too as below.
Note: You cannot define time zones and DST periods retroactively for time zones that are already used in contracts.
Having said that, we can try the below steps to achieve the requirement.
Note:
Please try the above steps in the test environment and after successful results as per the expectation, apply the same in production.