Since tax_id is now a default field in the sales invoice, orders and etc, my field created before as tax_id is now duplicated and I cant delete it because it gives an error saying that I have duplicated field.
Backup the data using CSV or any other method, then let the new field be added and after that restore the data from your backup file into the new column or use data import tool to update the data in tax_id column
I’m not concerned about the data stored in the old field, since is the same data in the new field, but the issue is that after the update I ended up with two fields with the same name