Upload & Sell: Off
I think there is a tool which does that. Should be possible to buy it in a dedicated film shop. Alternatively, buy an empty canister, and in a dark place, pop the top end off with a cheap beer opener, and move the roll of film into the new canister, making sure to leave a tongue sticking out, and then close the new canister. It might be possible to open the old one without damaging it, but you would never know until you tried it...
But... It might be possible to get it out manually with no special tools. If you turn the film with your finger, in the direction of taking it up, you will hear a click each time it gets past the hole. if you stuck something soft and wide a cm or two in, and then turn until it clicks, at that point you might be able to just wind it backwards and push it out, and it would glide out on whatever you stuck in, rather than hanging on the lip of the canister hole. It should be quite thin to avoiding damaging the felt which seals the light out. A piece cut from a thin sheet of relatively soft plastic might do it.