Change of Business Area to Cost Center (my first thread , please help)

Hi Everybody i'm Charmaine Leena Martin freshly certified FICO consultant , this is my first thread i'm posting, please help me with the same.

A wrong business area has been assigned to a cost center and postings have taken place in the same.

while using t-code KS02: change cost center , for rectifying the business area , i get the following error:

"Field change business area is not possible (transaction data exists)"

so i've created a new cost center and assigned it the right business

and using t-code kb61 : i have posted the documents to the new cost center

at that time system generates a co-document automatically:

But the accounting document of which transfer postings have taken place still shows old business area and cost center

Please let me know why is it so ,

and what has to be done with the CO document that gets posted automatically

and is there any other way out of changing the business area without creation of new cost center

Moderator: Please, search before posting