Why would you want to? If admins react to a call and nothing is happening they're not going to punish the reported player anyways without evidence; it's not like it does any harm. We can notice fake calls ourselves sometimes, but there is hardly any way to effectively report players who abuse the call and have them punished, since you would have to prove that the reported player wasn't doing anything. On top of that, 1 fake call does not get punished with much, so you would have to prove that of 2 or 3 of his calls before something even happens.
If you want to report someone who continuously abuses the call, though, you can do it through the conventional means, like report them on the forum or to an admin.