Cancel one leg of OCO and leave the other intact

[Zapzap]

I am using Unmanaged approach.

I have a pair of orders, tied together by OCO ids.
I would like to cancel one order only and leave the other intact.

Is it possible somehow?
ChangeOrder cannot delete an ocoid

Do I have to cancel both orders (well this happens automatically), and re-enter the one I want to keep?
*this works, however makes keeping track of orders in my internal registry difficult (since sometimes the old order gets cancelled later then the new one gets in)

[NinjaTrader_Bertrand]

Zapzap, your understanding of how this would need to be approached is correct, as you could not otherwise untie those orders. You could of course think about not using the OCO id in the first place but to manage this aspect fully yourself in the code, so cancel the one that is not needed anymore.