After you change an ad, if both Search and Content are enabled, when the ad resumes, will Search resume before the Content?
As Robsp mentioned, when you change your ad, it will then show only on Google until it can be reviewed and approved.
Once an ad is approved, though, it will show up on both types of partner networks at the same time. In other words, no, Search does not resume before Content.
After you change an ad, if both Search and Content are enabled, when the ad resumes, will Search resume before the Content? If Search impressions has resumed but not Content, what does it mean?
Good question. And a really hard one to answer, without seeing the account - so you may want to contact AdWords support with that question if you continue to have no Content impressions.
Assuming that you have double checked to make sure you still have the Content network selected, here is my best guess:
Is it possible that you have also changed the keywords in the Ad Group? Since ads are delivered to Content sites by virtue of an overview of all keywords in the Ad Group, then substantially changing the keywords can certainly affect where and how often your ad is delivered.
AWA