Hitting back space to redo a bad jury decision AFTER completing Jury Duty?

Twice in the last week I've realized I made a bad decision on Jury Duty and hit my "go back" arrow to try to redo my decision after completing jury service. I have a gut feeling this is really bad etiquette, and I'm not even sure it makes a difference since i don't know how the system works, whether once you've made your decision you've made it, or whether you can "redo" a bad decision.

Some people are making posts that at face value are inflammatory and derogatory, but when seen in context are merely sarcastic (and they are not using their sarcasm emojis). Sometimes, especially recently in the Primaries forum, there's so little to go on in some of these posts that it's sincerely hard to tell.

In the first instance, I realized I was wrong by thinking about it. In the second instance, the post was right there on the "Latest Threads" page and I looked at it and realized it was very likely sarcastic (or at the very least ambiguous).

I think the Jury system is brilliant and until very recently I haven't found it difficult. It's just some of the posts in Primaries are really close calls, and some are apparently sarcastic but without enough context to know for certain, and others are ambiguous.

EDIT: Also, sometimes the source of information in a post is at issue, and in one case it was difficult to research whether or not the source was credible.

I guess my question is can you redo a bad decision by hitting backspace, or once it is complete, it's over.

Thanks for any advice.