SELECT vs.* FROM (
SELECT CompanyID,BranchID,CustomerID,VisitDate FROM dbo.DMSVisitPlan
WHERE CompanyID =3
GROUP BY CompanyID,BranchID,CustomerID,VisitDate HAVING COUNT(CustomerID) > 1) dup
JOIN DMSVisitPlan vs ON vs.CompanyID = dup.CompanyID
AND vs.BranchID = dup.BranchID
AND vs.CustomerID = dup.CustomerID
AND vs.VisitDate = dup.VisitDate