Name              Sales
---------------------------------
    Thomas             100
    Jay                200
    Thomas             100
    Mathew              50

Name              Sales
---------------------------------
    Thomas             200
    Jay                200
    Mathew              50

'Combine duplicate rows and sum values

Dim Rng As Range
Dim LngRow As Long, i As Long
Dim pct As Integer
pct = 45

LngLastRow = lRow 'The last row is calculated somewhere above...

'Initializing the first row
i = 1

'Looping until blank cell is encountered in first column
While Not Cells(i, 1).Value = ""

    'Initializing range object
    Set Rng = Cells(i, 1)

    'Looping from last row to specified first row
    For LngRow = LngLastRow To (i + 1) Step -1

        'Checking whether value in the cell is equal to specified cell
        If Cells(LngRow, 1).Value = Rng.Value Then
            Rng.Offset(0, 1).Value = Rng.Offset(0, 1).Value + Cells(LngRow, 2).Value
            Rows(LngRow).Delete
        End If

    Next LngRow

    i = i + 1