Vasu,
This is an important issue.
In those situations where changes span multiple services then using feature flags to enable a feature make sense.
However, an essential characteristic of the microservice architecture is that the services are loosely coupled.
If you are regularly needing to change multiple services in lockstep that's an indication that your services are tightly coupled.
I'd explore ways to redraw your service boundaries so minimize the frequency of lockstep changes.
Another common refactoring is eliminating Data Services and "co-locating" data and business logic.
I'd be happy to talk more. And, I'm available for consulting :-)
Chris