Be very careful with relaxers. They can cause the hair to lose its body. I have used a relaxer on the sides of a full cap and it helped to tame the hair in that area, but if it had been used on the rest of the system I don't think I would have been able to wear it.

You can also change the position and curl of the hair with perming solution. I'm not sure how much different it is compared to relaxer, but I assume that the relaxer causes the hair to stay in a "limp" state, whereas the perming solution locks it back into a certain shape. If you do decide to try perming solution you have to make sure you don't use the neutralizer. After rinsing the perming solution it will neutralize itself by simply allowing it sit for 24 hours.

Not sure how much curl this would remove since there is no way to set the hair in a straight position other than by combing it in the direction you want. I would practice on an old unit first if you decide to do anything and BE CAREFUL! The hair has already been through a lot!