You can trade your Karma for Merit Points daily. Here's a guide on how you can access the Trading Office.
1. First, you need to go to the Administration Office and tap "Missions".
2. Tap "Trade" in order to access the Trading System.
3. Let's tap the "Trade Karma" for trading Karma to Merit Points.
4. Choose how much Karma you want to trade for Merit Points and tap "Trade".
5.If you are sure you want to trade your Karma, just tap "Yes".
6. Confirmation message will appear that you have successfully trade your Karma to Merit Points.
Always remember that there is a limit as to how much Karma you can trade per day. You can only trade up to 5000 per day.
Do you know that you can trade Units and Zel too? You can check the article for more details.