Crediting of Tax Amount of a line

Hi Gurus,

We are on R12.2.4 and we have the below requirement:-

I have a AR Invoice with total invoice amount of 1438 (Including Tax)

Line 1 :- Item 1000. Tax 190

Line 2:- Item 200. Tax 38

Now, i have a requirement to credit tax of 190 dollars against line 1.

How can we achieve this?

When i am creating Credit Memo, i can choose only 3 options (Lines Only, Line + Tax and Tax Only). If i choose Tax Only and then entire -190, then this tax amount is reduced proportionately from Line 1 and Line 2.

Regards,

Arvind