Here is an alternate way of repairing an end can if the carbon-kevlar tube is not totally junked and replacing is not mandatory. The part of the damaged tube must be removed. I would still be comfortable if the rest of it is 20cm in length at least. Use a piece of thick sandpaper to mark your cutting line. Any metal saw will do the rest of the job. The same length should be removed from the perforated pipe. And then welded back in again if necessary. And here is the end result.