The Expense Processor function, Audit, regular or manager, get you access to all reports. You can narrow it down by expense group, but not to a specific approver's direct reports. Are you trying to help the manager see past reports approved or reports currently in flight? They can already see past reports from their approval queue using the View option.
If it's something currently in flight or not yet submitted, I go down the delegate access option, but don't provide the option to submit. Most, if not nearly all my managers who do want it, just want to see or help their team so they can view the report directly versus screenshots, screen sharing or the dreaded retelling from the user perspective and lastly to quickly see what CC charges are sitting there.
