Yes they can
and should be lifted and replanted into a larger container. Just gently remove
each plant and retain as much of the soil attached to the feeder roots as possible.
With just a bit of care, it will be a very simple procedure.

Kent

Thank you! So I should remove all of them? Or could I leave one or two? And not sure if you can tell but in the middle there are three growing within millimeters of each other. I can just pull apart those?

Your container appears to be a bit small for adequate canna growth. I suggest you not divide the larger canna at this time. I can only assume this clump is growing from a single rhizome. If this is not the case then gently try to separate them. You can only determine this by lifting and inspecting the individual plants.

Kent