It should start delivering again almost immediately, but it may take some time for it to pick up steam. I had two ads going a couple of months ago that were averaging about 12,000 impressions a day and I got dangerously close to my total budget for the month with about six days to go. So, I paused them until after the first of the month. It took almost two weeks for the daily average to get back above 10K impressions. I think Amazon punishes you if you stop an ad.
It's like I was told a while back, NEVER terminate an ad. Amazon doesn't like that. Now you can pause an ad and change its end date and have it expire by itself. I've done that a few times when I've wanted to change an ad and didn't want two running for the same book. I haven't noticed any penalty for doing that.
