No, running requests cannot be put on hold and you have to wait for the running request to finish.
If you think that that the program is not required anymore and it is delaying your CM bounce, then you can kill the process.
You can use the abort option when shutting down the CM to kill any running jobs.
adcmctl.sh abort apps/apps_password
If we use abort option to stop concurrent manager what happens to the running request any data loss will be occured.
will it start concurrent manager properly again.
The abort option cancels all running requests and any unsaved changes will be lost.
Usually this won't cause issues unless you have custom programs that make changes and do several commits. In this case, the request will be cancelled and only part of the changes will persist.
After you shutdown the managers you can start them up normally and they will begin processing all pending requests.
Be aware though of anything which might be running as part of a request set, where earlier stages have committed. You could end up with data consistencies if you don't plan your restart correctly.