Be sure to have read and understood the solution set before you submit a regrade request. If you don't understand our posted solution then you are unlikely to understand why we think your solution is wrong. Feel free to meet with the course staff if you can't understand the posted solution set or if you can't understand the written comments the grader provided on your solution. The grade on your solution and/or changes to the grade are "out of bounds" topics for discussion at that meeting.
Resist the temptation to use regrade requests as a means to fish for a better grade. Any regrade request that we perceive to be specious will inspire increased rigor in rechecking your submission, and that often leads to a grade reduction. The course staff will go to great lengths to help you understand the course content; we are considerably less enthusiastic about discussing how what you wrote could be stretched to mean the right answer.