Spot channels convert to rgb mode

var doc = app.activeDocument;
MergeSpotChannels();
function MergeSpotChannels(){
    var spotChannels = [];
    for(var channelIndex = 0; channelIndex<doc.channels.length;channelIndex++){
        if(doc.channels[channelIndex].kind == ChannelType.SPOTCOLOR){
            spotChannels.push(doc.channels[channelIndex]);
        }
    }
    doc.activeChannels = spotChannels;
    executeAction( charIDToTypeID('MSpt'), undefined, DialogModes.NO );
};

This script works on documents containing Rgb + Spot channels. I just need a script that converts documents containing spot channels to rgb.  my english is not good I'm sorry :))