query SUM function issue/ grouping issue
Use your main query as a subquery:

SELECT EmployeeNumber,
       JobCode,
       [Date],
       SUM(Hours) as [Hours]
FROM
(
SELECT        tServiceReps.EmployeeNumber, 
              tServiceHours.JobCode, 
              tServiceReports.[Date], 
              tServiceHours.[Hours]
FROM          AdjustUserRoleRequestStatusLookup 
CROSS JOIN    tServiceJobCodes 
INNER JOIN    tServiceHours 
ON            tServiceJobCodes.ServiceJobCodes = tServiceHours.JobCode 
INNER JOIN    tServiceReports 
ON            tServiceHours.ReportNo = tServiceReports.ReportNo 
INNER JOIN    tServiceReps 
ON            tservicereports.employee = tservicereps.repid 
INNER JOIN    tRegions 
ON            tServiceReports.Region = tRegions.RegionCode
where         Date between '2017-10-03' and '2017-10-03'
and           EmployeeNumber = '10245'
GROUP BY      tServiceReps.EmployeeNumber, 
              tServiceHours.JobCode, 
              tServiceReports.[Date], 
              tServiceHours.[Hours]
) ctHours
GROUP BY EmployeeNumber, JobCode, [Date];