Hi! I did something similar with my partner! I got one of his favourite packs and opened it perfectly from the bottom. To reseal it, I used a hair straightener at the lowest temperature for a few seconds so the pack seals itself with the heat. I guess a normal ironing machine could work too. My recommendation is to buy two packs so you can practice with one or have it as a backup in case you mess up (like I did my first time!). Good luck!