Hi Yossi,
First you have to create the new work center (WC) in APO (send it through the CIF). Then, in ECC system you have to change the WC in the routing and prod.version (you change the old WC with the new WC).
To effectively change the WC in APO, you must re-send the PDS again through CIF integration model.
Thanks.
Regards, Marius