How can I edit a form that's been built with two languages?

Hello, I'm trying to edit a form that has been built in two languages, so when you fill it up you can select the language you want to in the upper right corner. The problem is that I can edit it in one language but I can't switch it to the other language in order to edit it too. 

I hope you can help me out. 

If you mean editing the translation, you can do that by going to the Form Settings > Show More Options > Language > Translations then click the Edit button. Here's a quick demo for your reference:

Thank you very much JohnRex!

Actually what I needed. 

Have a nice day! :)