Take off any potential seed pods. Leave the lilies in the pot, watering as before until the foliage dies down. You can then store them in dry peat until you want to plant them next year or just leave the pot in in an out of the way place before repotting next year or planting in the ground.

I'd do as above but give it a light feed to help it bulk up its bulb too.

which lilies are they? I also plant mine directly into the border, about 6" deep. they come through every year.

Thank you so much.Really appreciate your advice.