Wrong allocation cost element used at indirect activity allocation

Hello,

my company planned to change the allocation cost element for some activity types at year end. They forgot to do this. As a result they went for period 1-2 with the old combination. On march the created new activity types with new allocation cost elements. Now it is not clear how to post the values (period 1&2) from the old allocation cost element to the new one? Is this generally possible?

Thank you in advance for your help.

Kind Regards