Two different triggers for one check box

Hello, I find this community very helpful in the search function, but I haven't participated much with my own questions. I'm hoping you can help.

I have one check box that I would like to be triggered in two different situations "this OR that" kind of question. 

I have it programmed for one parameter, but I don't know how to make it work for two parameters. I don't want it to require both parameters in order to work so I was hoping there is an OR function similar to the AND function. 

Thanks for your help