G Lakshmipathi,
Based on my tests, I agree with siva vasireddy.
Just changing VBAK-WAERK would be sufficient.
It is not enough to change the document currency in sale order but also, you need to change the condition record simultaneously as otherwise, system will consider the currency from condition record if you check in condition tab of sale order.
Could you please explain why it would not be enough?
VBAK-WAERK is USD. Even if condition record has JYP; in the sales order in Tab Condition the currency and the value would be changed to USD (for final caculation; also in field WAERK).
As siva vasireddy has commented, the Net value would also be in USD (not in JYP).
Thus in my opinion, just changing VBAK-WAERK would be sufficient.