how to use pass vars

I’m trying to use pass vars to pass a variable as a parameter to a loop and can’t make it work.

The docs says [pass vars]{ANY_NAME}[/pass] but I need to pass it to the loop.

i.e. [loop type=company, author=this][set co_id][field id][/set][/loop]
[pass vars=co_id]
[loop type=company, field=’id’ value={CO_ID}]
do something here
[/loop]
[/pass]
what would be the correct syntax?