Cutover plan for Absence Type & Absence Quota Type codes

Hi Gurus,

Please help me in designing the cut over plan for changing the Absence Type & Absence Quota Type codes of the existing company of India. The Annual leave will be the only quota which will be updated through Time evaluation every month. The existing work schedules are old & there are also new work schedules created & moved to PRD. The absence quotas are linked with the work schedules. The client wants to use the new codes for absence types & absence quota types from 01.04.2015 along with new work schedules. Please give me the idea for the same. Thanks in advance.

Your suggestion will be really appreciated.

Thanks&Regards,

M.V.V