Using the text editor of your choice edit this file. This will create a new file CoalescedINT-export.ini in the same folder.
Note: might be smart to save the current code if you want to revert back to it later. Open a console prompt (cmd / PowerShell) and navigate to the folder where you extracted the app.\mecc 'C:\Program Files (x86)\Origin Games\Mass Effect Legendary Edition\Game\ME1\BioGame\CookedPCConsole\CoalescedINT.bin'. However, since the Leviathan DLC apparently makes it way more complicated, itd probably be easier to download and install the DLL patch, which, in addition to enabling DLC-based mods (and possibly being a prerequisite for editing the Leviathan coalesced file), enables the in-game console. Here you can modify Hair Mesh field with any of the below codes to replace your hair style. If youre sure you want to do it with coalesced, then the guide is in the PC Tweaks article on the Mass Effect wiki. INSTALLATION: 1) Go to your Mass Effect 2 Install Dir, then >BioGame\Config\PC\Cooked 3) MAKE A BACKUP OF Coalesced.ini 4) Move or paste 'Coalesced. Raw > Player > Appearance > Morph Head > Hair Mesh includes Coalesced.ini and original with a read me file.