Unless it's a one of a kind or stupid sentimental, I am not sure it'd ever be worth the time and money to try and disassemble a cue, hoping to un-warp it.
When cues warp, it's not because the joint gets tweaked or bent, it's because the wood was affected by moisture and has stressfully warped into a new shape. At this point, it's pretty much kaput.
It's probably possible, but the amount of time and money to do it, just buy a new cue.