If you have a dremel with a thin cutting disk you can make a straight cut across the head of stripped screw and use a flat head screw driver to remove it. An ez-out can work to, but theres more chance to mess up the triangle threads.
If the allen bolt head is rounded out you can use a pair of vice-grips to clamp onto it and get it loose and then unscrew it by hand. If you have stripped the threads in the frame they can be repaired with an helicoil. I have had to use an helicoil on a pm fork after hitting the caliper on a rock a stripping the threads.
An helicoil is a steel replacement thread that looks like a spring. The frame will need to be drilled. Some LBS may have the tools. I got mine done at an performance engine workshop where my brother works.
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