Can anyone tell me if there's a way to update the tax code/tax rate for multiple lines on a sales order? We just received a tax exempt certificate, and the sales order contains over 130 lines. Not sure if this can be done via CSV?

you can update sales order via CSV just get the line number/ or line sequence number in saved search

@Amanda Rosiak If you change the shipping address, then change it back, the tax will recalculate.