This variation includes two solutions for how to deal with existing content in cells being merged.
Private Sub TestMerge()
Dim i As Long
With ActiveDocument.Tables(1).Rows(1)
For i = 3 To 4
' .Cells(i).Range.Text = ""
.Cells(2).Merge .Cells(i)
Next i
.Cells(2).Range.Text = ""
End With
End Sub
The first solution deletes everything in cells 3 and 4 but retains content of cell(2). In the above code it is rendered mute by the apostrophe preceding the code.
The second way is to remove everything from the merged cells. I would recommend to run this version only while Application.ScreenUpdating = False
because it will cause a lot of flicker.
There are several more way, but in order to recommend the one most suitable for your needs one would need to have a better understanding of what you want. BTW, if at all possible, remove the blanks from the table at the time they are entered. Having blanks floating around your document and popping up when they are least expected or wanted is never a good idea.