Changing/correcting color on an older piece of art

[Meliara04]

Could someone tell me how to turn the photo on the right into the photo on the left? I see this style a lot and I'd like to learn how to do it. It looks like the blue has been turned to grey, and generally the colors have been toned down. I've tried a number of filters, but no luck. Everything I'm finding online shows how to make a grey sky blue, rather than the other way around. Appreciate any suggestions.

[c.pfaffenbichler]

A Curves and a Hue/Saturation Layer may achieve quite a bit, but I expect at least the sky may need addidtional masked Adjustments. 

[Meliara04]

That is amazing!! I wish I could even do that. I'll give it a try.

[c.pfaffenbichler]

Keep in mind that Hue/Saturation allows you not only to change the image globally but also to address different Color Regions separately. 

And you can manually change the affected colors by dragging the handles between the two »spectrum«-fields at the bottom.