przejść do wrogiego obozu

We shall now see how he turned his coat.

No doubt their king prepared to turn his coat, too.

"I'd rather see you dead than turn your coat like her next door."

I suppose so, unless he does turn his coat once he's free.

I've never turned my coat on any of them.

And he began to wonder- What if the man had turned his coat a second time?

"Thought I might have turned my coat again, is that it?"

If so, when had she decided to turn her coat?

When a man turned his coat once, it took no great stretch of the imagination to think he might do so again.

More likely you could turn your coat in the service of the Patriarchy.