(list-set! lst pos item)

list-set! sets a list item (using position number) to a new value

Parameter	Description
lst	List to be changed
pos	Item position to be replaced
item	New item to be placed in position pos

Example

Example 1:

> (define lst '("a" "b" "c")) 
> (list-set! lst 1 "d") 
> lst
("a" "d" "c")