Simple type question..?

Example:

Type mytype
  Field a, b
EndType
Function test(x:mytype)
 'Here do something to x:mytype
EndFunction

Function Blah()
 typ1:mytype = New mytype
 typ2:mytype = New mytype

 typ1.a = 10
 typ1.b = 5

 'Make typ2 like a "temp" of typ1
 'Change typ2 without(!) changing anything in typ1.. 
 typ1 = typ2 'Does not work

 test(typ2)
EndFunction

In C I would do something like:

struct mytype
{
char a;
char b;
};
void test(struct mytype *ptr)
{
// Change something
}
void Blah(void)
{
 struct mytype typ1;
 struct mytype typ2;
 typ1.a = 10;
 typ1.b = 5;
 
 typ1 = typ2;
 test(&typ2);
}

The typ1=typ2 thingy is my problem. It makes them identical
but when I change something in either typ1 or typ2 the other also change.. Not what I want.. Anyone??