Profit center not changedater

A material was having profit center A. Scheduling agreement was created against it and GR was done. While creating the invoice it was determined that the profit center for the material should have been B. So the GR was reversed and and the profit center was changed to B in the material master. Now when we are trying to post the GR again..it it still picking the wrong profit center- A. Why is this so? How can this be corrected?