This is not an approved method, since there isn't a an approved method for recanning. However, every time someone has some jam or jelly that doesn't set or that doesn't seal, they give the following directions.
If it didn't set, either cook it down or add more pectin, reboil, put in sterilized jars, and water bath can.
If it didn't seal, bring the contents to a boil, put in a new sterilized jar, new lid, new screw cap, and water bath can. (use this method)
If it was me, that's what I'd do. (Good catch on getting all that jelly and jam! What luck.)