I am currently trying to save the trigger changing the number of retries and interval of retry. I first ran the service with a different set of parameter and its currently in retry schedule. When i tried to change the trigger parameter even thought its locked, It sets to old parameter.
My question is whether we cannot change when the documents are there in trigger queue. In that case, let me know how to clear the documents from trigger queue which is scheduled for retry.
Thanks
I guess YES. Integration server does not allow you to change the trigger properties when its running execution service. The reason might be,when a existing client is deleted and new client is created when we can change the trigger properties. This may lead our guarantee deliverly to go on toss as its Broker(clients 
) waits for the an acknowledgement from integration server. Anyone please correct me if I am wrong.
Also While Integration Server retries a trigger service, it ignores requests to shut down the server until the trigger service executes successfully or all retry attempts are made. This allows Integration Server to process a document to completion before shutting down.
You can clear the document in the queue from Broker Admin page.
Thanks for the analysis and I tried browsing through the Broker admin page and not able to find out where to delete the documents piled for retry. Let me know where you saw the option to remove documents. Thanks!
follow following steps to clear document queue
1.get name of trigger which subscribe for that document.
2.Find Client option under Broker srever in left of screen.
3.Click on Documents in Queue for client craeted for above trigger.
4.see at top u will find clear queue option.
Thanks for taking through step by step. I cleared the documents and able to edit trigger settings.