Hi @sally sally,
You can do that by using invokeHTTP processor, once you make first service call then keep Response relationship to trigger next service.
This way we can only triggers next service once we get response from previous service.
Example:-
In my below flow service 1 is triggered by GenerateFlowFile processor then i connected response relationship to trigger service2 InvokeHTTP processor. This service2 processor only triggers when it got response from service1 processor and keep in mind the response from service1 will be overwritten by response of service2.