How can I partially close a Trade?

If you have opened a trade on MT4 and would like to change the Lot size of the order after it has opened. You can do so by following these steps:

1) In MT4, right-click on the Order in the Order List that you would like to change, and select the “Modify or Delete Order” option

2) Set the Volume amount you want to close. Change the “Type:” to “Market Execution”, and then click the yellow close button