What code have you tried? Is there ONLY 1 dash or hyphen in the character string. Is the length of the variable big enough to add 2 characters to the value? Here's one possibility but it will only work if there is exactly 1 dash in the value:
Walk in ready to learn. Walk out ready to deliver. This is the data and AI conference you can't afford to miss. Register now and save with the early bird rate—just $795!