The tour departure date and duration can be changed from the Tour Information section within the Tour Settings window.

Simply clicking on the  button will load the tour settings and bring up a new window where the departure date and number of nights can be changed.

The departure date can be changed by either typing over the existing date or by clicking the adjacent arrow to activate the calendar and select the new date.

The number of nights is changed just by changing the number in the nights box.

Once the required amendments have been made click the button to save.

From this window the tour can be attached to an existing route already in use by another tour.  This procedure is further explained in the FAQ on changing routes.