flash to html5

I don't see any specific reference to flash ad to html5 in the ad module.
Of course I have flash ads rotating. I would like to simply delete the flash ad and replace it (or back it up) with the html5 version without trashing the whole ad and starting over. Yes, I know. . . in some parallel universe. . . Flash seems to override. I do find flash to html5 backup modules.

If the module does this I don't see it referenced and I'm not in the mood to experiment.
Then, if I have to start over will it even work with this module and would the code go into the "body" input area? What happens if I delete the flash version? Will it default to html5 or leave a blank area?

Would appreciate any input.
MikeB3945