This seems like a Group By case, Could you try with the below Expression using an Assign Activity :
OutputDT = (From d In DT.AsEnumerable
Group d By k=d("Wage Type Text").toString.trim, l=d("Associate Name").toString.trim Into grp=Group
Where grp.Count > 1
Let sumValue = grp.Sum(Function(x)CDbl(x("Amount").ToString))
Let ra = grp.First.ItemArray.Take(grp.First.ItemArray.Count-1).Append(sumValue).ToArray
Here DT is your input data from the Excel sheet and OutputDT is the Clone of the Input datatable.
Cloning of the OutputDT could be done in the below way :
OutputDT = DT.Clone
This needs to be done before using the above Expression.
For handling errors related to direct CopyToDatatable, you could check the below post :
Let us know if you are not able to get the Expected Output.