I used to be able to do this in Photoshop CS6 by simply clicking the check boxes in the "image size" dialog box:
(all boxes UNCHECKED)
Then input the dpi (usually converting a 300dpi print file to 72dpi for web). And the pixel dimension will stay the same.
In CC the only option I see is "scale styles" which does not apply to the pixel dimension of the file.
Please help. I would hate to have to do this function in CS6 all the time.
Just uncheck the [ ] Resample checkbox, then change your Resolution.
Change the units from Percent to Pixels if you want to see pixel dimensions.
Once you've successfully run it through (after OK), note that it will remember your units settings the next time you use it.