BreakSideBySide Method [Excel 2003 VBA Language Reference]
Ends side-by-side mode if two windows are in side-by-side mode. Returns a Boolean value that represents whether the method was successful.
expression Required. An expression that returns one of the objects in the Applies To list.
The following example ends side-by-side mode.
Sub CloseSideBySide() ActiveWorkbook.Windows.BreakSideBySide End Sub