This example resizes the selection on Sheet1 to extend it by one row and one column.
Worksheets("Sheet1").Activate
numRows = Selection.Rows.Count
numColumns = Selection.Columns.Count
Selection.Resize(numRows + 1, numColumns + 1).Select
This example assumes that you have a table on Sheet1 that has a header row. The example selects the table, without selecting the header row. The active cell must be somewhere in the table before you run the example.
Set tbl = ActiveCell.CurrentRegion
tbl.Offset(1, 0).Resize(tbl.Rows.Count - 1, _
tbl.Columns.Count).Select