swapping earbuds from old broken cable to new earphone cable

Hi. I’ve been sent a new earphone cable for my Fairphone earphones for my Fairphone 3. All I have to do is swap the earbuds from the old to the new cable but I’ve tried twisting them off and nothing is happening and I can’t find any instructions anywhere for this! Can anyone help? I find it so odd that self-repair and modularity is such a selling point for Fairphone but they seem to make it so unnecessarily obscure?!