Need Advice on I94 related question

[G8nOldW8n4GC]

My parents are here visiting me currently.

They have Multiple Visa good till May 2010.

The duration of stay on their I94 is till Dec 12th.
They are leaving to Canada to visit my sister next month.

My question is will their I94 be taken away at the port
and issued new ones when they come back in??
Trying to find out whether they can stay in Canada past Dec 12th
or do they need to get back in before Dec 12th.

Please quote sources if possible.

Thank you

 

[Triple Citizen]

Their I-94 will not be taken from them, but they can always surrender it.
How long they stay in Canada will depend on the entry granted to them. Default is usually 6 months.
If they surrender their I-94, they will need a fresh I-94 to re-enter.

My question is will their I94 be taken away at the port
and issued new ones when they come back in??
Trying to find out whether they can stay in Canada past Dec 12th
or do they need to get back in before Dec 12th.