Summarize:

Press down your popsocket to flatten it against the back of your phone. It will be easier to remove it in this compressed form. Do not try to remove the popsocket while it is extended, which may result in it popping out of its base. Choose one corner of the popsocket and gently start peeling it up. Gently continue pulling in a circular direction, pulling up the outer surface. Once the entire radius of the circle is unstuck, pull up the popsocket to remove it. If the adhesive is too strong to remove the popsocket by hand, slide dental floss under it to unglue it. Wrap the ends of a long piece of dental floss around your index fingers and position it at one edge of the popsocket. Gently but firmly pull the floss between the popsocket and phone, breaking the seal. Make sure that the adhesive part of your popsocket is clean so that it will re-stick properly. Gently rinse it under cold water and let it sit for 10 minutes to dry. Be sure to attach it to another surface within 15 minutes or the adhesive will dry out. Choose a new spot for your popsocket, on the same phone or on a new one. Press the popsocket down firmly to let he adhesive part stick to the phone. Continue putting pressure on it for 10-15 seconds to ensure that it adheres properly.
Flatten the popsocket before removing it. Gently peel up the popsocket from one corner. Use dental floss to remove the popsocket if you can't pull it off. Rinse and dry your popsocket if the adhesive part is dirty. Stick the popsocket to a new surface area.