Multiple entry Canadian and US Visa needs extension of stay??

[sffpine]

My parents have multiple entry Canadian visit visa valid till April 2012,and multiple entry US visit visa. They entered Canada on May 21, 2011. The bottom of the stamp has Nov 20,2011 date, they went to US on August 25th and came back on Sept 02. Now they left Canada on Oct 08 and plan to stay in US till Feb. then will be back to Canada for a couple of months before they go back to their own country. Do they have to go to the border and apply for the extension of stay before Nov 20 or will they get new entry stamp whenever they want to enter Canada after Nov 20,2011. My sister and I live across the border in Windsor & Detroit, so they might want to visit just over the weekend.

[PMM]

Hi

My parents have multiple entry Canadian visit visa valid till April 2012,and multiple entry US visit visa. They entered Canada on May 21, 2011. The bottom of the stamp has Nov 20,2011 date, they went to US on August 25th and came back on Sept 02. Now they left Canada on Oct 08 and plan to stay in US till Feb. then will be back to Canada for a couple of months before they go back to their own country. Do they have to go to the border and apply for the extension of stay before Nov 20 or will they get new entry stamp whenever they want to enter Canada after Nov 20,2011. My sister and I live across the border in Windsor & Detroit, so they might want to visit just over the weekend.

As long as their multiple entry TRV is valid, they will be admitted to Canada up to it's expiry date in April/12.