Any list function that specifies the default delimiter (a comma) for its arguments, is an optional argument, and as such, will not need to be provided. For example, you could use:
<cfoutput>#listChangeDelims( 'to,from', '<br>' )#</cfoutput>
And the above will assume the list is comma-delimited (which it is), and replace it with <br>, however, this too is under the assumption that CF is being used to generate HTML rather than plain text. Set the mime type accordingly.