On 17 Sep, 19:00, Jeff Layman wrote:
Water it well first, then put it on its side and whack the container all
round to loosen the pot from the compost. Then (as Sacha suggests) hold
it by its stem and tap the pot rim all round. *If this does not work,
then just cut the container away. *

Another good trick is to let it get a bit dry, then roll the pot on
it's side a bit, taking the weight of the main stem by hand. Often as
you stand it up it comes loose enough to lift out.