IDIQ

Yes, but if you have already meet the minimum, just don't issue them anymore orders. Once the minimum is met you aren't any legal obligation to continue to use it.

CDS is correct, but do you need to terminate an order under that IDIQ which is not yet completed?

Maybe.

Are you talking about the parent contract, or orders under the parent contract?

Does the contract include the clause at FAR 52.212-4? Or the clause at FAR 52.249-1, -2, -3, -4, -5, -6, or -7?

"Yes, but if you have already meet the minimum, just don't issue them anymore orders. Once the minimum is met you aren't any legal obligation to continue to use it"

provided it is not a multiple award IDIQ and you don't have to consider the contractor in question when placing orders.