Negotiations with Airbus Canada are currently ongoing. However, you don't want to unsubscribe, just postpone it.

Czech Airlines has to thwart its plans and restructure itself. To do this, it is necessary that any contractual partners also show that they are accordingly cooperative. Negotiations are currently in progress with aircraft manufacturer Airbus in order to have the delivery of four A220 aircraft that have been ordered later.

But these are still not dry, as reported by ch-aviation.com. In the same breath you also emphasize that you do not want to cancel the order, but only postpone it to a later date. In the long term, one is planning with the aircraft models. The new date should be set at the end of the year.