[Q] SD Card

Probably the most NOOBISH question ever... but here goes and any help would be greatly..... greatly appreciated.... ive rooted (woo hoo i know lol) ive installed CM9, all the stuff is on SD card, can i remove the SD card and re-partition it? i think ive set 25 out of my 32GB card as the wrong kind of memory :D
probably really stupid thing ive done lol