I did this when I worked at Christus Health. I had to create mapping tables for cost centers, accounts, capital numbers, project numbers. We even had new PO numbers. The biggest challenge in the beginning was getting on a full ERP system with location in the GL String. We used a combination of cost center and location (entity) for our new cost center. For the initial mapping some old cost centers might need to be allocated to few new cost centers. Not all cost centers were able to be mapped one-to-one. I would be happy to help if I can.
#ApptioPlanning(ITP/ITFMF)