Keep in mind if the previous world was before mistlands, the same seed won't be quite the same now. Landmasses are pretty much the same, but some biomes are shifted and bosses probably moved.

Or you will reset the world by using backup If you load the (worldname).old yur world will be untouched as it was on the first day

I believe you mean you want the same world but want it to be new again? If so, all you need to do is put in the same world seed number when you create a new world.

Originally posted by GoldieHeart:

I believe you mean you want the same world but want it to be new again? If so, all you need to do is put in the same world seed number when you create a new world.

OK...away ATM moment. Will I be able to get the seed if I renamed the world?
Sorry for being so needful.....one of those days

When you are at world selection screen, you see a list of worlds, featuring the name you gave them and their seed.

Create a new world and input the seed you want to copy.

Thanks....I successfully navigated a Home Depot defective product encounter w/o killing the employee who asked, "what do you want us to do?" Good day so far!