Firstly, this is a mute point unless you are addressing this post to a coder with access to the back end. The maximum report function limit is not a control panel setting and sits in the function_all.php file. For anyone to change it they would need access to the coding section and it would be silly to give anyone that.
Secondly, the maximum of 3 reports is the software default setting. I don’t think tinkering with default settings is something that’s wise.
Finally the default setting is restricted to stop reporting abuse and that is very wise. Mods enter rooms to 50 plus reports sometimes, it takes a while to go through all the serious ones and the serious ones are generally reported by many users. 3 per person is a good arbitrary figure. It could be 2 or 4 but really?
Anyway - it can’t be changed and shouldn’t anyway.