This example creates a table in a new document and indents the first row 0.5 inch (36 points). When you change the left indent, the cell widths are adjusted to preserve the right edge of the table.
Set aDoc = Documents.Add
Set myTable = aDoc.Tables.Add(Range:=Selection.Range, NumRows:=3, _
NumColumns:=3)
myTable.Rows(1).SetLeftIndent LeftIndent:=InchesToPoints(0.5), _
RulerStyle:=wdAdjustSameWidth
This example indents the first row in table one in the active document 18 points, and it narrows the width of the first column to preserve the position of the right edge of the table.
If ActiveDocument.Tables.Count >= 1 Then
ActiveDocument.Tables(1).Rows.SetLeftIndent LeftIndent:=18, _
RulerStyle:=wdAdjustFirstColumn
End If