The workbook has already 4 worksheets: Plan and 3 reports.
In the first worksheet (plan) with a toolbox combobox the user will choose 1
of 4 options:
Jan-feb-march
apr-may-june
july-aug-sept
oct-nov-dec

when 1 of 4 options is choosen automatically other 3 worksheets shoud
receive respective names: say apr, may, june and in a cell of each worksheet
should appear April, May or June correspondingly.