I can't find any posts about this issue, but it may be that i don't know the right keyword to describe what i want to do. i'm just coming to the end of a very successful warp, and i'm thinking it might be nice to just make another warp in same tie up but different colors. so i'm thinking i can just cut off the old warp and tie the new threads to the old threads, then wind it on. I don't know if this process has a specific name. But i'm wondering if there's a video showing it, in case there some tricks i need to know to make this go smoothly. thanks.

Dummy warp. Jane used a dummy warp for the mohair.
episode 9.2 in season 1
I remember she has a loom just dedicated to mohair and a dummy warp for it.

And Handwoven magazine and I'm sure many others have posted their version of a dummy warp.

good way to also have less warp waste when using nicer yarns too.

good luck!!!

I have done this with a complicated threading that I didn’t want to rethread but wanted to use again with different colours. As long as you have enough warp left over to use for the dummy then go for it. It was very successful for me. I had no problems at all. I warp front to back so I tied on in front of the reed and the knots slid through the reed and the heddles without much resistance and wound on easily. No loose threads, no rethreading of heddles. If you do decide to do this then best to open a shed when winding the knots through the reed and the heddles so they don’t have to go through all bunched together on the same plane.