How to edit the reminder formula?

The reminder formula is a ready-made template on which the reminder text will be built upon. Un4gettable will generate the SMS Text according to this formula, using the variables between the dollar signs as place holders. For example if you create an event at 1/1/2016 10pm, at 12 king george st' NYC and your SMS formula is: "Hi, just reminding you we meet at $DateTime$ $Location$" The SMS Text will be: Hi, just reminding you we meet at 1/1/2016 10pm 12 king george st' NYC.