Replacing trainable units with techtreemods

Age of Empires III: DE III - Modding
1

I understand how to add units to a civ, however i’m stuck on replacing them. I want to replace the crossbowman in Act 1s civ with pavisers.

2

Merge mode replace?

3

Can “mergemod replace” replace a tech/unit? For example replace “GuardDragoons” with “NewGuardTech”? Or can I only replace icons and name? If so, how?