There should be a date field when a ticket is selected status Pending. So that when a ticket is suspended and it reaches that date, then the ticket automatically sets itself to Open. I would also suggest that in the Admin section that a Business Hours auto unsuspend date is able to be selected e.g. if your agency or company has a policy to follow up after 3 days then you should be able to set it to do this for every ticket set to Pending to automatically unsuspend after that time-period, unless a specific date is set after Pending is selected. That way if someone is away till a certain date, you can set it to unsuspend on the day after their return to follow up.

I would also suggest a reason for Pending e.g. Pending Customer Response, External Action Required, Change in Progress, Major Incident Resolution, etc. That way it is clear why the ticket was set to Pending and can be reported on.