Leaving a war

[Party All The Time]

Can I just voluntarily leave an ally's war after it's started?
I see the CPU leaving wars all the time, but I can't figure out how to do it myself or if that's even possible.

[Delta-Kilo]

To the best of my knowledge, it's not possible for you to leave a war once it's started. The best you can hope for is to not send your troops in, ignore the conflict, and hope no one attacks you. If all goes well, you'll have some diplomatic constraints while this goes on. The worst outcome would be your ally is engaged in a defensive war and they note you've not come to their aid, causing a breaking of your alliance and a prestige hit for you.