I've never used it, but if you are joining straight to the tables you can use 'SQL Expressions' which hopefully will convert it. For display you could write a formula, but I don't know if that will work with a chart (my company doesn't use charts, just lots of numbers).
if you are getting the data from a stored proc, just change it in your stored proc, or add a column something like:
CASE WHEN Event_Status = 'active' THEN 1 ELSE 0 END AS newColumnName
added to a select statement should work.