How to choose between two variables randomly, to assign the value of a third variable?

Is it possible to randomly choose between two variables, the one that will receive the value of a third variable?

I thought to use the "set value", but in the first field I can only select a variable instead of writing a command line, otherwise I could use "choose" for that.

Yep choose goes in the second field, the value. The first box is to choose the variable you are changing.

I need "choose" to go in the first field because the value would be the third variable. What I need is to randomly choose one of the two variables mentioned and assign the value of another variable to the chosen variable

Can do it with events, set a local variable to choose(0,1), if 0 change variable 1, if 1 change variable 2.

Thanks for the suggestion. I will do it.