Hello Dhiman,
Access to anonymous tasks:
http://<server>:<port>/webdynpro/dispatcher/sap.com/tc~idm~wd~workflow/AnonymousService
Direct task access:
http://<server>:<port>/webdynpro/dispatcher/sap.com/tc~idm~wd~workflow/AnonymousEditTask?TaskId=<TaskId>
Hope it helps.
BR, Keith