Creator Multi Select

Creator Multi Select

How do I add and remove data from a multiselect field with deluge ?

I want users to tick a box to "pin" a row so I have constructed a lookup multiselect box that addes users who have pinned.... if they untick the box I want to remove the current user while leaving any other values the same.

This is my code for adding the current user > it's on a "user input of field" action
  1. // ADD LOGGED IN USER TO MULTI SELECT
    varCurrentUser = Add_User[users_zohoid == zoho.loginuser].ID;
    if(input.documents_pin == true)
    {
        input.documents_pinnedusers = varCurrentUser;
    }
    if(input.documents_pin == false)
    {
        //???
    }