Hey, the same thing happened to me. I wanted to retake O. Chem II since I didn't do too well on it (6 years ago). The Student Records Office told me to fill out a "Petition to Repeat a Course Form" at my CC.
I picked up a form, filled it out and when I went back to turn it in, the secretary told me I couldn't repeat the course if I had already received a passing grade.
I didn't like that answer, so I asked to speak to a counselor. He disappeared into the back and came back and told me that (per the counselor), I could take the class but it would have to be on a pass/fail basis (not graded).
Uhmmm... no. How would the pharm schools see an improvement if they just see a "P" on my transcript.
I was adamant and requested to speak to the counselor personally. After a few minutes, the counselor finally came out and told me that I could take the class and it would be graded, but the new grade will not count towards my CC GPA. (I wonder how valid that statement was. It seems like they did not know what they were doing over there. I'll see whether it was averaged in when the grades are posted.) Good enough for me. Pharm schools calculate GPA independently anyway.