You only have the option to build an itinerary starting "today" and forward.
We have occasions where so much changes while the client is in country that we would like to be able to duplicate the itinerary and provide a new, clean version of the itinerary summary midway through the stay.
This will allow us to show all the changes from the old summary to the new summary and ensure our client understand the changes in costs.
But at the moment the dates don't align as we cannot start the new build on the correct day of arrival as it is in the past.
Only way around this currently is a PDF editor since we cannot export the Itinerary Summary into any other formats.