Hi Aarthi,
In a synchronous message flow the process is not completed until the request and response is completed.
In your async to sync bridge, IDoc triggers async request and then a sync webservice is called, with the requestResponseBean in your webservice receiver channel , the process will wait for a response. if anything fails from request untill response, the whole async process fails, and can be resend from PI.
Once the response is received successfully, the control is passed to another process as defined in the responseBean configuration.
This process would be async process (I don't think a reason for this to be sync) and if this fails, can again be retried within PI.
