There are certainly changes that cannot be rolled back such that the affected users are magically fixed, which is not what I am suggesting. In the context of mission critical systems, mitigation is usually strongly preferred. For example, the Google SRE book says the following:
> Your first response in a major outage may be to start troubleshooting and try to find a root cause as quickly as possible. Ignore that instinct!
> Instead, your course of action should be to make the system work as well as it can under the circumstances. This may entail emergency options, such as diverting traffic from a broken cluster to others that are still working, dropping traffic wholesale to prevent a cascading failure, or disabling subsystems to lighten the load. Stopping the bleeding should be your first priority; you aren’t helping your users if the system dies while you’re root-causing. [...] The highest priority is to resolve the issue at hand quickly.”
I have seen too many incidents (one in the last 2 days in fact) that were prolonged because people dismissed blindly rolling back changes, merely because they thought the changes were not the root cause.