What type of glue did you use? If you used Epoxy, use a heat gun on the joint. The Epoxy will soften and you can pull the joint apart. Be careful, and be ready to repair the covering if you end up burning a hole in the covering.

If you used CA, you can try using CA Debonder along the joint. It will take a while to soak into the joint and soften the CA.

If you used wood glue/titebond, you can try soaking the joint with water. Those glues tend to weaken with water, but again it will take a while. Heat will also soften wood glues. You will then have to make sure you give the wood ample opportunity to dry out.

Brad