Mod requests (orders).

ok :)

0. Copy the original archive somewhere so you can restore it if something goes wrong.
1. Take the DeadKnight_c.zip archive and open it with WinRAR / an equivalent.
2. Unpack or simply drag DeadKnights_c.h5u out with the mouse to some location.
3. In that location, right-click on the obtained file / open with / WinRAR_or_equivalent.
It's advisable to check the box to open similar files, so that all *.h5u files can be opened with a left mouse click.

3. Using the file system inside the archive, navigate to the GameMechanics folder, then Creature, then Creatures.
There will be two folders - Necropolis and Neutrals.
Inside them are .xdb files.

These files are opened with a text editor, and they contain structures like this:

<tag> text </tag>

There are also nested structures, but you just need to change the text.
For example, attack is located here 

<AttackSkill>23</AttackSkill>

The tag names more or less indicate what they are and what they control.

At first glance, the Knight parameters are preserved as original - they just changed their abilities.

The abilities are located inside the tag 

<abilities>

at the bottom of the file.
Essentially, you just need to swap the contents of abilities.

3a) note
For the deadly grip ability, in addition to abilities

<Item>ABILITY_HARM_TOUCH</Item>

, you need 

<KnownSpells>
		<Item>
			<Spell>SPELL_ABILITY_HARM_TOUCH</Spell>
			<Mastery>MASTERY_ADVANCED</Mastery>
		</Item>
</KnownSpells>

This is present in the file GameMechanics / Creature / Creatures / Neutrals / Death_Knight.xdb .  If it seems complicated, you can just look at it by analogy.
To compare PARAMETERS with the originals, you can open the file ...\Your_Heroes\data \ data.pak with an archiver, and follow the exact same path for the Death Knights or Knights. Do not modify the original files from data.pak under any circumstances!

4) The essence of the change is to modify the text files using copy / cut / paste.
5) After that, save the file, and the archiver will ask "Update in archive? Yes / no?", press yes.
6) Put the resulting DeadKnights_c.h5u into the folder ... ...\Your_Heroes\ UserMods and see what you get.

7) If something went wrong - restore the original archive from step 0, delete from UserMods  and keep doing it until it works.