DON'T tap the joint. You could create small hairline fractures in the carbon. Here's some ideas.
1: Try pouring hot water over the joint for a minute and then pour cold water over the joint. A good sharp twist should dislodge it. Sudden expansion/contraction might allow the sections to slip apart.
2: Tie some elastic band round the blank, on either side of the joint. This gives you something to grip.
3: Get someone to hold one section, firm and steady, while you twist the other section.
4: Wave the pole gently overhead, like a fly rod. This sometimes allows the 2 sections to come free.
5: Try a Teflon lubricant, like GT85, sprayed into the join. Allow to penetrate for 5 mins, wipe clean and then try again.
 NEVER EVER! Try to Twist a stuck pole section,in most cases it will lead to breakage, if you have 6" sticking out, you have enough to hold onto, in which case get an assistant to hold onto the 6" protruding and pull, while you hold the other section and rapidley tap it sharpley with 2/3 fingers, the Object of this, is to shock/ jar the stuck section free.
I agree with groundhog, never twist stuck sections. The way i release stuck sections requires 3 people, 2 to take hold of each end of the pole and pull against each other and the third person to hold the pole between them and wind it (windy miller style)It may take a while but it does work with no damage to the pole!