How to change moves of an ark/monster?

Hunter Island FAQ
1

I’ve noticed some arks have more than 4 moves. Can I choose which ones to use? Because only 4 shows up during battle. Thanks!

2

please check some of the attacks are passive moves. that means they will be triggered on event (like when the ark is going to be killed or it always give some atk/def)

3

Thanks

4

You can change moves by giving the ark HM or TM, hang on that’s pokemon lol…

The answer is there’s no way to change moves or add new moves manually, they learn new moves through evolution & units might have 1-2 passive moves & therefore not showing up in battle.