You should be allowed to swap to beige whenever you like. But as a balance you can only leave after (amount of time) and after you leave can declare war after (amount of time).
You should be able to swap to the Beige whenever you want, but if you do swap you can't leave for (amount of time) and you can't declare wars for (amount of time). In reality this just makes sense as getting wars constantly declared on you is extremely annoying and can just cripple you.