Finding Most Recent Date From Current Date?

the requirements are to return person ID with the most recent leaving date from a scheduled dept, who has previously arrived at an unscheduled dept within 7 days, but just now my query shows all the previous leaving dates within 7 days of that unscheduled dept arrival, I only want the last leaving date before the arrival at the unscheduled dept:

So for instance looking at a copy of one person's date below I have:

PersonID Last Dept Arrival Date To Last Dept Leaving Date From Last Dept Next Arrival Date to Unscheduled Dept
======== ================= ========================= =========================== =====================================
0106573268Dept 5 2013-03-01 2013-03-03 2013-03-05
0106573268Dept 6 2013-02-27 2013-02-27 2013-03-05
0106573268dept 2 2013-02-26 2013-02-26 2013-03-05

In the data above I only want to return the first row, which is the most recent leaving date before arrival at an unscheduled dept.

My query is much the same as before except my inline view is looking at the data for last scheduled leaves from depts in my inline view and also the outer query returning all arrivals to the unscheduled dept:

SELECT b.personID
,b.dept AS "Last leaving dept"
,b.arrival_Date as "arrival Date To Last dept"
,b.leaving_Date AS "leaving Date From Last dept",
a.[arrival Date] as "Next arrival Date to AREA_GH"
FROM Unscheduled_Arrival a INNER JOIN (SELECT *
FROM scheduled_Leaves
where [leaving date] is not null) b
ON a.Person_ID = b.Person_ID

[code]....