How can I set my trade to close at 21:00 GMT?


Hi, I want to know, how to set my open trade so it will close automatically at 21:00 on certain date? The expiration section in pending order only close the trade if the trade is not open at certain time. However, once the trade is opened already, it won't close unless it hit take profit, stop loss or closed manually. I already search at Google for this, but all I can find is a technique using complicated coding. I want it to be simple easy to understand.