Closing part of a multiple lot order.

 
OK, this has always bugged me about multiple lot orders, but I'm unable to come to a definitive conclusion so I've been placing 2 orders at the same price for multiple lot trades. Lets take a long trade for example. If I buy 10 lots can I close out only 5 of that order if I placed the order buy order for 10? If so is it as siomple as placing a sell limit for 5? I had a problem once before with this but my broker has had problems with MT4. Now I just started placing multiple orders like say 5 and then 5 more so I could set different profit targets. Walk me through this will you? Thanks!
 
I was having the same problem. Seems to me the way to do this, is to right click trade, choose Close Order> Change Volume Size to how many to close, and then click Close#blahblah button

Remaining open lots will read in trade window comments (split from order#blahblah) and Account History will read in comments Partial Dose

=)