I think there is a problem with terminology here.
Every code-share is the subject of an agreement.
There are three kinds of code-share agreement: parallel, connecting, and unilateral.
An example of a parallel operation is Qantas and LATAM operating SYD-SCL.
Each operates flights on the route and each sells seats on the other's flights with their own code.
An example of a connecting code-share is Qantas and AIrFrance from Australia to Paris via Singapore.
QF operates flights from AU ports to SIN. AF does not.
AF operates flights SIN-CDG, QF does not.
But each airline can sell flights for the entire route, using their own codes on the sector operated by the other airline.
An example of the third is the arrangement between QF & EK.
QF operates no flights PER-DXB or DXB-CDG, for example.
But you can book a ticket PER-DXB-CDG on flights operated by EK using the QF code.
But in this example, the term "unilateral" is a reference to the mode of operation of the flights.
Unlike in the first two examples, QF does not operate any of the flights in the third example.
In that sense, the operation of the flights is "unilateral".
Only EK operates the flights.
However QF cannot just sell seats on any other airline's flights with a QF code without their permission.
Even a "unilateral code-share" must be the subject of a code-share agreement.
Which may also be subject to regulatory approval.
So if NZ has withdrawn from its code-share agreement with QF, QF cannot simply decide to continue selling tickets on NZ flights with a QF flight number, as if nothing had happened. That cannot be a unilateral decision.
