How to recant a global variable which has been declare?

RouterOS Scripting
1

I’m a beginner,Reply,if you please! Thanks!

2

http://wiki.mikrotik.com/wiki/Manual:Scripting#Variables

3

Thank you! I will try to refer the manual first!

4

Sorry, I have read the manual, but I can not find the answer!

I would know that how to cancel the declarations of global variable , so that the global variable can’t be seen with execution of “environment print” in terminal console. In the 2.9.27 version ，which can be used: “:global variable_name” to achieve .

5

there is no point to use such an old version of RouterOS. Update to newer version.