Try this one.
I supposed that data is column A and B and start at row 1. the result
will be in the new sheet after activesheet.

Sub movedatatest()
Dim acsh As Worksheet, dstsh As Worksheet
Dim i As Long, j As Long

Set acsh = ActiveSheet
Set dstsh = Worksheets.Add(after:=acsh)
acsh.Select

lastrow = Range("A1").End(xlDown).Row
j = 1
i = 1
dstsh.Cells(j, "A") = Cells(i, "A")
dstsh.Cells(j, "B") = Cells(i, "B")
For i = 2 To lastrow
If Cells(i, "A") = dstsh.Cells(j, "A") Then
Cells(i, "B").Copy
dstsh.Cells(j, "B").Insert Shift:=xlToRight
Else
j = j + 1
dstsh.Cells(j, "A") = Cells(i, "A")
dstsh.Cells(j, "B") = Cells(i, "B")
End If
Next
Application.CutCopyMode = False
End Sub

keiji

Skipper wrote:
how to make loop (macro),
raw
13035 13031
13035 13037
13036 13056
13037 13251
13037 13298
13037 13299
13044 13282
13075 13275
13048 13031
13048 13055
13099 13066
13099 13077
13099 13252
13099 13692

result

13035 13037 13031
13036 13056
13037 13299 13298 13251
13044 13282
13075 13275
13048 13055 13031
13099 13692 13252 13077 13066