Include VAT conditionaly

Hi all,

I have a small tricky work, that I had VAT included in all invoice by
default, but I also need to create invoice without VAT.
If I am sending a blank “sales_tax_rate” parameter then, I am getting a
invoice with “0” VAT,
but I want to hide that part strictly Don’t want to show VAT in a
conditional Invoice.

Please help in this case,
ASAP