How can I adjust a character model using Unreal?

I got a character asset online but the head and arms arent the right size for the animations I’m using, but any time I adjust them in Unreal it never seems to save (Mesh window tab) and it’s from 3ds Max which If I have to open up again I might throw my computer at whoever designed that awful (Sorry if you use it) program XD All I want to do is change the size of the characters head and arms, which the Mesh window seemingly lets me do until it matches what I need, but no matter what way I save it or what I click it doesn’t actually change the model. As you might be able to tell I’m fairly new to all this so I apologize if I don’t understand an answer that seems simple, I’m trying to learn Unreal and really dont want to learn a entire other program just to slightly alter a few body parts.

You can’t make adjustments to a skinned model that way, you’d usually have to adjust the mesh and then reskin it to the skeleton. The only other way you can change it would be with morph shapes

That is unfortunate because 3DS max does not like me and I cannot for the life of me figure out how to make these adjustments but I guess for now I will suffer with a bobble head and stubby arms XD thank you for the answer though

There’s other 3D software that you can try like Blender or Maya, but most likely you just need to practice more with it, if you’re new then it’s going to take some time to learn how to use a program. If you’re wanting to get into 3D work it just takes time.