I have setup a worklow where there are three roles. End-user A sends to userB. User B can then either accept/ reject or ask for feedback. However, when user A provides the feedback user B again needs to either accept, reject or ask again for feedback. Basically the workflow starts again (is triggered again) once feedback is provided.
How can this be implemented in SharePoint designer via workflows?
Kris,
Usually these kind of Workflows where there are different states involved with the Item, which are not sequential and can switch to any state at any point in time are called State Machine Workflows.. Unfortunately there is no way (AFAIK) in SharePoint Designer to make State Machine Workflows but you have that in Visual Studio..
If you want to go for State Machine Workflows, Please see:
Creating SharePoint 2010 State Machine Workflows in Visual Studio 2010
SharePoint 2010 State Machine Workflows with Custom Task Forms (InfoPath) using VS 2010 - Part 1 of 3
PS: You haven't mentioned the SharePoint version, so I assume it to be SharePoint 2010
