SharePoint Approval Workflow Custom Tasks

Hi All,

I am using SharePoint Designer 2010 workflow. I need some guidance for adding custom tasks for out of the box approval workflow. 

I know that we have "Change Request" and "Reassign Task" option in our of the box workflow. Requirement is to add a task where a user can request for extra time for approval.

An author uploads a document for approval to his manager with default due date to be 5 days. Manager should be able to request more time if he couldn't approve it before that time. For which a request/task should be assigned to author to approve it.

I modified the Task form to add a view for "Request time". My question is how to create a task for the author.

Any help will be appreciated.

Thanks