Updated: 09/08/2016. WeChat recently added a functionality in the app to remove your account.
We’ll show you in this guide step by step what you will need to do to delete your account:
1 Open the WeChat app and select ‘Me’ in the menu
2 Tap on ‘Settings’
3 Choose ‘My account’
4 Scroll down to the bottom, where you will see: ‘Delete account’
that you want to reset your account and delete your whole conversation history with it.
5 Mark that you have read the terms and choose ‘Next’
6 Enter your WeChat ID, password and the captcha
7 Leave a reason for removal and tap on the ‘Remove’ button
You’ll see a message appear: Account has been deleted.
As your account has been closed, you’re now free to remove the app from your device if you want to.
Source (& thanks to): WeChat app for iOs iphone