CALL

sub subName zero or more comma separated parameter variable names
  'code for the sub goes in here
end sub

This statement defines a subroutine.  Zero or more parameters may be passed into the subroutine.  A subroutine cannot contain another subroutine definition, nor a function definition.

The CALL statement is used to access the SUBROUTINE and to pass values into it.  The values must be the same type as the SUB statement defines them to be.  So the following example:
  sub mySubName string$, number, string2$

is called like this:
  call mySubName "string value", 123, str$("321")

