preventive plan scheduling

Dear Experts

please a i need urgent help am new the PM module

my customer need to make the new preventive plan for 2015

the case is : the current preventive plan for year 2014 will end at 28/12/2014 (the last order )

so i advised him to make the new scheduling after finishing of the last order 28/12/2014 but the problem is that he need to present the new preventive plan in 25/12/2014 so if we make the new scheduling before 28/12 the orders of this day will be rescheduled so how can i make the new preventive plan with avoiding the loss of the rest orders in the old plan

Best regards

Hossam Ghanem