It doesn't, because you aren't supposed to. If they Cord in the water didn't work it could be that they were not drinking enough, which is very common when they are sick. When I have one that's not drinking enough, I give it undiluted orally (I have an article about that too).This is the post. But I didn't see anywhere where it says to take a break from treating.
It's also possible that the strain is resistant to Cord, so you need to treat with something else like Baycox (tolrazuril) or a sulfa antibiotic.