Once you are “colonized” there will be an eight hour suppression period. During this time you can have your allies’ mass troops and you can build up your own army. Once this time is up there will be a fight between the attacker’s troops and your own. If you win you are free and if you lose you become a colony under the attacker, your suzerain.
So obviously you want to win the fight, right? Well if you get your allies to reinforce you, you may take losses but win in the end. I’d rather not take any losses. So here’s the trick: go to your Embassy and you will see where troops are garrisoned in your city. You will see your attacker’s troops. You simply have to dismiss them.
The catch is that if you do this right away and your suppressor notices they will simply reinforce and hope you don’t notice. The key is timing. You have to wait until the last minute so that your suppressor doesn’t have time to reinforce. When suppression ends and the stabilization battle takes place your enemy will have no troops in your city and you will win as a result.
Give it a try and let me know how it works for you!