Change the Voxel size and image dimensions

Hi,

So my original image dimension is 256x256x207 with voxel size 1.21875x1.21875x1.231. I wanted to change the same image to become 400x400x109 with voxel size 2.036x2.036x2.027. How can I do that? I've been trying to do this for weeks now but I don't know how to. Can anyone give me an idea?

Thank you so much!

[Adam]

What do you mean by voxel size?