Amending Tax Amount during voucher match

Hi All,

We have lot of purchase order, for which Taxes are applied via Landed Cost.

1. Purchase order is created

2. Received into Stock

3. Applied the tax to the PO by applying Landed Cost via P43214

4. Government has revised the Tax percentage

5. During voucher how to revise the tax amount, can we revise the Open Amount in P0411 ( which comes during 3 way voucher) according to the revised tax percentage.

     If Tax amount is revised, will it have any impact on the Financial side.

Thanks in advance.

Abdul