How to override Tax classification code value as per certain instances ?

Hi Support,

I have received business requirement to override the tax classification code from one tax  to another tax rate code as per bill to location of the customers. Below i have describes the requirement in details.,

At item level we have updated the tax rate code for every items as CGST+SGST tax rate. And as per the setup for every sales order line for each part tax rate code defaulted as CGST+SGST. But there are certain instance where tax rate code should be IGST and there are almost 75% sales order for which users are changing the tax rate code at order line.