The reason the box stayed greyed out is because you didn't pick the old padstack in the board file instead of using the list. Try the following script. Replace "my_new_padstack" with your new padstack (note that the padstack name must be in quotes). When you run the script, the command window will say "Pick origin for macro". At this point you pick the center of the via you want to replace (your grid must be fine enough to accurately pick this via). The via will be replaced with the padstack name in the script file ("my_new_padstack" in my example). If you're doing multiple replacements, you may want to turn off On-Line DRC, then turn it back on when you're done.
# Allegro script
# start time: Tue Apr 11 17:09:25 2006
# Version: 15.5 s047 (v15-5-81BV) i86
version 15.5
setwindow pcb
trapsize 155
# Macro file: coordinates are relative to pick on replay.
replace padstack
pick_origin
pick rel grid 0.00 0.00
setwindow form.mini
FORM mini newname_browse
fillin "my_new_padstack"
FORM mini viamode YES
FORM mini replace
setwindow pcb
done
# stop time: Tue Apr 11 17:09:55 2006
Originally posted in cdnusers.org by Randy R.