How to modify pending order lot size?

[zoom20092]

Follow as

If last sell trade opened

Modify Buy stop lot size to X2.

Sorry for my English.

Thank you very much.

[fxDreema]

This is the function to modify orders: http://docs.mql4.com/trading/ordermodify
Open Price, SL, TP and Expiration can be modified, but not the Lot size. So... close the order and open a new one.