modal

components.list-item.js

import Ember from 'ember';

export default Ember.Component.extend({
});

components.see-more.js

import Ember from 'ember';

export default Ember.Component.extend({
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  array: [
    { text: 'one', more: 'i am the number 1' }, 
    { text: 'two', more: 'i am the number 2' }, 
    { text: 'three', more: 'i am the number 3' }
  ]
});

templates.application.hbs

<ul>
  {{#each array as |item|}}
  	<ListItem @item={{item}} />
  {{/each}}
</ul>

<!-- I want to call see more just one time and update the data inside of it-->
<SeeMore />

templates.components.list-item.hbs

<li>
  {{@item.text}}: 
  
  <!-- Call modal here-->
  <a href="">more info</a>
</li>

templates.components.see-more.hbs

<div class="modal">
 <h3>{{@item.more}}</h3>
</div>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}