FS00 - change tax category from < to * problem

Hi we need to allow all tax postings for one GL account, original setting was: tax category "<" and we need to change that to "*" but when doing so we are getting a hard error that there is balance on the account and we can not change that. There is no open item management on that GL account also. Is there any way to handle that? we can not create new gl account. thank you