How do i keep my plant alive after harvest Help quick please

I just want to know what to do to keep my plant alive after i'm done with it in flowering im harvesting the rest right now and i want to keep one in case my seedling doesnt work out 24 hrs dark then reveg right?

See this link in the Grow FAQ: GROWFAQ

There is also a thread where someone is trying this here: https://www.rollitup.org/grow-journals/79451-1st-time-regeneration.html

i heard if after u harvest a plant and leave major stems and the main stalk it will regenerate, that be awesome if growin outside