Racket: `remove` element from list on a text file

Question

Problem Description:

I am encountering a problem trying to remove my item from my list. The list was previously written to a text file using call-with-output-file and is now being read using call-with-input-file. After reading, the list looks like this: ("a" "b" "c"). The element should be removed with remove.

Code:

Read/Write:

(define lst
    (call-with-input-file "todo.txt"
      (lambda (des)
        (read des))))

(call-with-output-file "todo.txt" #:exists 'update
       (lambda (out)
         (write lst out)))

Removal:

[(equal? action "remove todo")
     (display (~a "Choose an ToDo to remove:\n" lst "\n"))
     (remove (string-trim (read-line)) lst)
     (call-with-output-file "todo.txt" #:exists 'update
       (lambda (out)
         (write lst out)))
     (display "Removed.")]))

Expected Behavior:

I expect the program to write the new list in my text file.

Actual Behavior:

My program overwrites the file with the same list as before (no deletion, no error).

Thanks for any help! -Till