I have a scenario where I want  three approval levels for a particular request.
Like for eg.
For the first time , a user login in and create a request, then we will invoke a workflow process in which we have 3 approvals to
approve the request. At first time mail will be send to 1st approver when user will submit the request.
Now when the 1st approver logins in and see the request in his task list, he should able to change the status and an email will be send to 2nd approver.
Then approver 2nd Logins in  and see the request in his task list and change the status of the request and then passes the same to
approver 3rd.

So my problem is when the user logs out after the submission of request and 1st approver login in and when he change the status of request I have to call the workflow process again, because of this I am not able to understand how can the workflow process will be executed from the current state of the process rather than calling workflow from the beginning.

So how can we maintain the session for the process as when the 1st approver comes in , he will be able to perform his task according to flow defined in the process as Human-task.

Is it possible or not ?

Thanks & Regards
Pardeep Ruhil