How do I alter keyframes for a new framerate? I created a new scene for a new animation. I didn't know this at the time, but a new scene is a new world, so settings will be back to default. I made all my weapons, models, HUD elements, and others with the default settings. Whats the problem with this? I have 60 fps for my animation framerate, but the new scene has it on 24.

Yes, I should simply increase it to 60 to match everything else, but all my animations will run faster than 2x regular/intended speed. I could set it to 60, and do whats on my mind: delete and rework all of the tons of animations I have created.  I obviously am looking to an alternative, and I am thinking that, hopefully, in some way, I can take an animation and maybe move the frames or have all the frames moved by a percentage (example: original frames = 10, moved by 150% makes total 15 frames)?
In object mode, select all the objects for which the animation rate needs to be changed from 24 to 60 fps.

In the graph editor, place the 2D cursor at frame zero, and set the pivot center to 2D Cursor

Hit A once or twice to select all of your keyframes. (You may want to hit CtrlH to hide the curve handles if it looks too busy)

Hit S, then X to scale horizontally, then type 2.5, then Enter

This scales your 24 frames-per-second animations out a multiple of 2.5 to 60 frames-per-second.