Well, from what I have read, it depends on how much of a difference it would be. If it is something small, like iono, you made a typo, I would forget about it.
If there are big changes, I would definitely email someone in admission's office for help. I did it for UCL, and although I did not receive a reply back, they did add it on!
dinostrea reacted to kittythrones in Possible to Augment Applications after Submitted?