Hi Amrita
You cant update it in COPA doc, once the FI doc is posted. You will have to reverse and repost your FI doc
Regards
Ajay M
PS: Request you to close your threads once your issue is fixed. you can close by marking any of the relevant answer as CORRECT ANSWER. For any workaround solution, you can specify it as HELPFUL ANSWER.. Incase no solution is available, Close your thread by marking it as "Assumed Answered" . This helps others in future to know how the issue was resolved
Hope you will do your bit for a better SCN