A simple JOIN should work.
DECLARE @LookUpID int
SELECT sp.SalesPersonID,
sp.FirstName,
sp.LastName,
a.Address1,
a.Address2,
a.City,
...etc....
FROM dbo.SalesPersons sp
--LEFT?
JOIN dbo.Addresses a ON sp.SalesPersonID = a.LookUpID AND a.RecordTypeID = 3
WHERE sp.SalesPersonID = @LookUpID