Using miles for a CDC on a DL reward flight using VS miles

Am a confused Tonty at the moment.

I've used my miles to get a G to NYC but flying on DL (flight times suited me better) hut I'd also like to use some of my miles to get the CDC which you can do on VS flights but the page on the website says no CDC for code share flights but that is for paid for flights but I've used miles

So does anyone have any experience of using VS miles for a CDC when flying on DL but on a VS reward. The flights are on the DL flight code.

I recently used miles for CDC in NYC after flying on a reward flight with VS.

Before traveling reward seats came up on the earlier DL flight and I rang to change to it. I was told if I changed then the CDC would be cancelled and I would be refunded the miles, as you can’t have the CDC using miles if travelling with DL.

I stayed on the later VS flight to keep the CDC.

[mitchja]

A CDC isn't an option on any type of Delta One fare as far as I'm aware.