Change state by route link

controllers.application.js

import Controller from '@ember/controller';
import { inject } from '@ember/service';
import { set } from '@ember/object';

export default Controller.extend({
  
  state: inject(),
  
  router: inject(),
  
  actions: {
    resetMessage(route) {
      event.preventDefault();
      
      if (this.router.currentRouteName !== route) {
        this.router.transitionTo(route);
      }
     	
      set(this.state, 'message', this.state.defaultMessage);
    }
  }
  
});

controllers.ofc.js

import Controller from '@ember/controller';
import { inject } from '@ember/service';

export default Controller.extend({
  
  state: inject(),
  
});

router.js

import EmberRouter from '@ember/routing/router';
import config from './config/environment';

const Router = EmberRouter.extend({
  location: 'none',
  rootURL: config.rootURL
});

Router.map(function() {
  this.route('ofc');
});

export default Router;

services.state.js

import Service from '@ember/service';
import { reads } from '@ember/object/computed';

export default Service.extend({
  
  defaultMessage: 'Initial State',
  
  message: reads('defaultMessage'),
  
});

templates.application.hbs

<span {{action (mut this.state.message) this.state.defaultMessage}}>
	{{link-to "Go to OFC 1" "ofc"}}
</span>
|
{{#link-to "ofc" click=(action (mut this.state.message) this.state.defaultMessage)}}
  Go to OFC 2
{{~/link-to}}
 |
<a href="#" {{action "resetMessage" "ofc"}}>
	Go to OFC 3
</a>

<hr/>

{{outlet}}

templates.ofc.hbs

<button {{action (mut this.state.message) "Has Changed!"}}>
	Change State
</button>

<div>
	{{this.state.message}}
</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"
  }
}