Re-trigger SAP Work flow after partial approval of PR

HI,

I was trying to re-trigger the Work flow after changing the Quantity.

for example below is the level of approvals and the limit I have.

Level                          Limit

1                                1 - 1000

2                                1001 - 5000

3                                 5001 - 10000
         

1. Now, I have entered the PR quantity as 9000 ( which is last bucket ) and partially approved till level 2 (so here till level 2 was approved )

2. and then I have changed the Quantity to  5001 (Which is same bucket ) and saved the PR. But the approval levels shows still the same level 2.

But here I'm expecting to start the approval level from level 1, when I change the Quantity from 9000 to 5001.

Could some please provide me the pointers.

Regards,

KV