a mother plant is a plant u keep for clones
and yes rejuvenation is possible
leave as many leaves as possible while harvesting the top buds
leave bottom smaller buds this is where new growth will sprout
switch back to veg cycle and be patient
new growth will look funny but it will grow out of it
You dont have to flower a mother plant. The idea is to let it sit under decent lighting and pop clones from it to work with. You can re-veg but I have no experience with that. I personally dont flower my mothers just so I have them sitting idle for when I need a clone of that set of genetics.