How to un-do outlines fonts?

Always save 2 files, the original file in the text file and the copy file with the created outlined text, The printer normally asks for the outlined text file so it will not ask for the fonts, 

What I ldo .. before I outline the text I will copy all of the text into a new layer (does not need to have an artboard) make that layers visibility hidden. That way you only have to have one document which has the outline text and also editable text

Outlining fonts is a sometimes necessary evil. What I've learned to do is duplicate the type BEFORE i outline it and move that duplicate text to its own layer. When I turn of the layer, Illustrator does not trouble with it, does not say I'm missing fonts, ignores it basically. Then I go ahead and outline the original  type that's on the original layer. If anyone comes along and asks for a change, I can switch my hidden type layer back on and work with text. If it gets shipped anywhere else and they don't have the font, the can at least turn on the layer and check the type specs and the name of the missing font.

Just a good working practice.

No. You will need to retype the text and reformat. Now you know not to do that in the future and to tell all your designers not to.