title: How can I change the data between ViewControllers as an action?
body: <p>I am having a problem with passing data between ViewControllers as an action. This shall mean following: </p>
  
  <pre>ViewController1 - NavigationControllers, etc. - ...
                                                   |
                                                   |
  ViewController2    -     -    -    -    -   -   ...
  </pre>
  
  <p>So I have two ViewControllers. ViewController1 has a variable (let's say var myName:String = "Joana")
  and I want to change it by clicking on a button in the ViewController2.
  My question is: How can I do that (I know how to pass data between VCs which are directly connected via a segue, but not combined with an action, that's my problem)?
  I've heard of prepare(for segue: UIStoryboardSegue, sender: Any?), but I think that it only works if there exists a segue (directly) between both VCs. 
  Summarised:</p>
  
  <p><code> VC2: Button: action -> change var 'myname' on VC1 to 'hello', no direct segue.</code></p>
  
  <p>Thanks for your help in advance! :-)</p>