I got a requirement from our client that their approval workflow needs backup approvers. It means the approval task is assigned to a group(one of them is the primary approver), if by any reason the primary approver cannot finish the task(e.g. he didn't do anything in 5 days), then this approval task will be automatically re-assigned to other user/users in this group. Can this be done?
The default approval workflow doesn't do what you want as far as I know. But it wouldn't be too hard to create a custom one using SPD. If it's a sequential flow, you'll get there with designer. If not, you'll need Visual Studio.