Changing the direction someone is looking.

[Egnazio_Rogers]

Hello,

This is a cropped photo for the new Avengers Endgame movie. It shows Robert Downey Jr "Iron Man" looking into the distance. I was wondering how I would make him look straight ahead instead of off to the side.

Thank you, Egnasio.

[c.pfaffenbichler]

Clip the iris and pupils onto Layers of their own (one for the left, one for the right) and fill in the missing parts.

Paint in the white of the eyes where the it is and puppies currently are on a Layer of its own.

Create a Layer Mask aperture of the eyelids and apply it to a Layer Group into which you put the Layers from above.

Convert the iris Layers to Smart Objects and transform them as needed.

[Egnazio_Rogers]

Hi c.pfaffenbichler. I was wondering whether I could turn his whole head to face forward not just his eyes. Thank you.

[c.pfaffenbichler]

Maybe you have seen some presentations online about automated 3D interpretation of faces in single images (reaching back more than a decade) but those features have not been implemented in a Photoshop-release as of yet.

3D morphable model face animation - YouTube

3D Portraits - Adobe MAX 2015 - Sneak Peeks | Adobe Creative Cloud - YouTube 

[Trevor.Dennis]

You could copy the head to a new layer, fill in behind the copy, and Free Transform the copied head.  I think I have him sort of looking in the same direction as the other characters, but that is such an intense stare. 

[Trevor.Dennis]

Incidentally, I used the Smudge tool to pull the background behind the new head.  Where those straight lines are top right, I used the age old trick of using the shift key.