Modify edit/close/remove button on activities calls

Can anyone point me in the right direction to add custom action items to the Activities subpanel calls “edit/close/remove” button? I would like to add a item “push forward one week” to this dropdown so I can easily push forward a scheduled call a week. I am having a hard time tracking down where the code even is for this

What version of SuiteCRM (7 or 8) are you using?

7, I ended up loosely following this guide I found though it is not perfect it works enough: How to Add Buttons to Views in SugarCRM