system
Given the following post, respond as if you're commenting on Reddit:
human
[Superman/DC Comics] Is there a reason Superman can't like, get The Atom to enlarge Kandor?

Superman just keeps an entire shrunken city in his alien house until he can figure out a way to enlarge it.......... Why can't he just ask Ray Palmer to do it? He can shrink and, obviously grow.

Has this actually been addressed in canon anywhere?
gpt
Kandor was shrunk by Brainiac using a method that was apparently incompatible with Ray Palmer’s white dwarf star matter technology. Presumably, any attempt to enlarge Kandor using it, would have proven fatal to the Kandorians.  
Also even if it wasn't incompatible, Atom may not be able to do it: Just because he can shrink/grow himself and like a car doesn't mean he has the power to do an entire city, that's several orders of magnitude harder.  
Also depending on the continuity, Atom's power has a time limit.  After growing them, if he didn't shrink them back in an hour they'd explode.