In the ksh, you will probably need to set up a couple of aliases if they are not already set (list aliases using the alias command), as follows:

alias history='fc -l'
alias r='fc -e -'

This will then allow you to list previous commands by typing history, and recall a prev. command with r xxx (where xxx is either the number of the command in the history list, or the first few characters of the command).

In addition if you issue the command set -o vi then you can use the escape key to get into 'command line editing mode' from there, use vi navigation keys (k for prev. command, j for next, l for cursor right, h for cursor left), and vi editing keys (x, p, r etc.) to modify commands.

HTH

David.