If you need to scratch an Event or a Race during a meet, you can do so by setting the "scratched" flag in the Event or Race. You should also set the comment for the scratched Event or Race so that it will appear on the schedule the next time you print it. To set these values for Events, use the Events tab. To set these values for Races, use the Schedule tab. When you reprint the revised schedule, you probably want to use the "Revised" annotation on it.
There are three ways to scratch a competitor from an Event, depending on when it happens. If the scratch happens before the lane assignments have been printed up and distributed, such as if it happens at the scratch meeting, you can simply delete the Entry for that person in that Event. You can do this from the Entries/Progress task in the Entries tab.
If the scratch happens after the lane assignments have been distributed but before the first race of the Event, you can set the "scratched" flag in the Entry for that competitor. The competitor's name will still be printed in the reports for that Event, but with a line through the name. You can do this from the Entries/Progress task in the Entries tab.
If a competitor is scratched from an Event after having raced in at least one Race in that Event, you should enter that as an exception in the Results task of the By Event tab. Select that tab, then select the Event and Race and select the Results task. For the Entry to be scratched, change the Exception value to SCR for scratched. The SCR indication will appear in the results column for that competitor in that Race only. Results of other Races are not affected.