If you have a group with only one ad, then those keywords will be affected by the ad's exposure as they'll have to wait to be shown on partner sites.
If you have more than one ad in the group, then the 2nd+ ad will show on partner search sites while you're waiting for the edited ad to be approved.
You then keep checking the "served" percentage of the ads and when it's clear the new ad is showing regularly, the ad it's replacing can be deleted.
Despite saying that, just 5 minutes ago I went and edited an ad for a silly reason when I clearly should have created a new one.....
patient2all