Awaiting Acceptance is managed via a workflow called "HRI Case User Acceptance." I have no idea why it was done this way, but that's what we have. There is a timer activity where it defines that it's going to take 2 business days before auto-closing. You could modify that workflow with branching and/or scripting to make the timing do whatever you want (based on HR service, COE, phase of the moon, etc.).
