How can I edit an existing replacer?

[Stopgame]

How can I edit an existing replacer? Is it possible to do this through a game editor like Racemenu? At least send a guide. It would be better if it wasn't a guide on creating a companion.
Like this replacer:
https://www.nexusmods.com/skyrimspecialedition/mods/127181

[IsharaMeradin]

It depends on what aspect you want to edit. 

• Creation Kit / xEdit would be needed for editing any records within the plugin.
• NifSkope, possibly Blender or other robust 3D software, and, if lucky, BodySlide would be needed for reshaping any meshes.
• GIMP or other DDS editing software that uses the correct compression ratios for editing the textures.
• a surgical overwrite of the mod's provided files with something else. <-- this would need to happen regardless of file source (direct edit or taken from another mod).

There is no in-game menu that I am aware of that can edit individual aspects of an NPC.  But I also haven't kept up to date on everything made available over the years.  So... perhaps more explanation on what you want to do would allow for better detailed responses.

[scorrp10]

What exactly do you want to change?  Some things are pretty easy.  Some really require having the source preset.  

[Stopgame]

19 hours ago, IsharaMeradin said:

It depends on what aspect you want to edit. 

• Creation Kit / xEdit would be needed for editing any records within the plugin.
• NifSkope, possibly Blender or other robust 3D software, and, if lucky, BodySlide would be needed for reshaping any meshes.
• GIMP or other DDS editing software that uses the correct compression ratios for editing the textures.
• a surgical overwrite of the mod's provided files with something else. <-- this would need to happen regardless of file source (direct edit or taken from another mod).

There is no in-game menu that I am aware of that can edit individual aspects of an NPC.  But I also haven't kept up to date on everything made available over the years.  So... perhaps more explanation on what you want to do would allow for better detailed responses.

I want to create a replacer based on a preset. I also want to make a preset from a ready-made replacer.

[scorrp10]

The first one is quite easy.     The second is about impossible.   In case of the replacer you linked, your best bet is contacting the author (Farodadestin) about getting the preset.   If you have a replacer mod, it is not too hard to alter that replacer to change the weight, body shape, hair, eye color, brow shape, skin tone(to an extent).    The head parts are usually not too hard to figure out, and head shape can be imported from existing head mesh.   But the tint mask, including all the contouring, makeup etc, can be a real bear to replicate.   

Now, I don't have much of a guide that I follow, most guides I know of are done on LE via NifMerge, such as this one:   

 

Except what I usually do instead of NifMerge, is create my own copies of used head parts in CK, and then manually rename the mesh parts in NifScope to match.