Hello Ravi,
In addition to Parveen's reply, alternate option is to reverse and repost the JEs which has wrong functional area determined
,
For JEs created for the transnational document then You can
Open the Journal entry,
Click on You can also and select View business transaction for accounting
Click on View all
Here you will have the Buttons 1) reverse and re-post and 2) Reverse and re-post to another period
This will reverse the original JE and create the new JE with correct GL/Functional area fi the settings are changed after Original JE was created. However this needs to be performed for each JE.
Regards,
Harshal