Reassigment of account assignment element Funds Center not possible

Dear all,

We are activating Fund management former budgeting in a live system.

We need to update FM data (fund center, commitment item, fund and Earmarked Funds) on purchase orders that ALREADY have goods receipt.

FMCN seems to work however FMCT returns error messages:

We need to update this value in order to be able to post subsequent GR.

Thanks!