You create a routing, which is valid from 01/01/2000 through 12/31/2000. The header comprises initially of just one change status. You subsequently change the header several times using change numbers:

1. You change the header with a change number that has the Valid-from date 05/01/2000.

The header now comprises of two change statuses with the validity periods 01/01/2000 through 04/30/2000 and 05/01/2000 through 12/31/2000.

2. You change the header with a change number that has the Valid-from date 09/01/2000.

The header now comprises of three change statuses with the validity periods 01/01/2000 through 04/30/2000, 05/01/2000 through 08/31/2000 and 09/01/2000 through 12/31/2000.

3. You change the header with a change number that has the Valid-from date 05/01/2000 again.