I am using an answer block
You can't, or at least that's all I know. But you can still create a variable "answer" and change it when the answer changes, that way you can treat the variable like the answer block but now you can change it.
Well, if you're using the answer block, using the ask and wait block
And then pressing enter could "technically" reset the answer.
That's the best way I can explain it.
Okay, but what if the user just doesn't?
Right, you have a point.
My idea with using a variable still works, though.
True, yeah.
One method is to load the menus library and then do something like this
I don't understand. I ran this and it reported an error.
edit: apparently it doesn't error if you leave it blank, good idea
Interesting - what happens if you just click on the empty ask reporter?
Do you get this?
I forgot to leave the reporter input blank. oops.
Actually - its much simpler than I first thought
does the same job 
That's easier than what I thought too.
This may be possible with JS but otherwise there isn’t, which is really weird given just how open snap is
(Maybe a
Option in the future?)
What I said about variables could replace the "my answer" block. Also, the block is global, meaning all sprites report the same answer. so it'd be better to put the block in sensing instead of variables.
Aside from making a new block there’s nowhere, and that doesn’t seem like something they would do
Well, it worked for me, and he did mark my comment as the solution.
I was saying if it was to be added that’s how it should be
Ok. That's reasonable, adding that block would just make it like a variable. So maybe they could just save it to a variable instead, but I'm not sure which category they would put it in. Or they would make the ask block a reporter instead of a command, that way it can be in sensing but you can assign it to a variable, but that's already a custom block.