In this task, you are given a list of unique integers you need to swap the positions of maximum and minimum element in the list and return the updated list.

[304, 238, 225, 39, 179, 446, 165, 139, 69, 450, 51, 374, 188, 193, 68, 259, 433, 464, 127, 63]
[304, 238, 225, 464, 179, 446, 165, 139, 69, 450, 51, 374, 188, 193, 68, 259, 433, 39, 127, 63]