No mulligans. No take-backs. No do-overs. When you are dealing with an accrediting program, once you have something on their official transcript, it's.... well.... official. Even if your child does really poorly, it's still part of their "permanent record." (You have to say that so it's all scary-sounding, like rolling thunder or something. "...Permanent Record." ) Colleges will ask you to submit all transcripts for all schools, and even a rotten transcript is a "real" transcript that has to be submitted.
That's one reason why I prefer homeschool transcripts. We can re-take a class, or a test, or a semester without reporting how many tries it took. In homeschooling, only the results matter, not the process.
If you do have some truly rotten grades on an official transcript, consider having your child re-take the class. Teach it again at home, until your child has mastery. It may take a long time for them to learn, or they may catch on pretty quickly the second time. Once they have an understanding of the concepts, then you can provide grades again. If you do that, it would be a wonderful thing to explain in an application essay. Talk about stick-to-it-iveness, perserverence, and the love of learning that homeschooling provides.
We are taking some time this week to write our first homeschooling high school e-book! I look forward to introducing it soon!