At the outset, it is important to know that after you have had a high ratio insured mortgage for three years, even if you've extended the term several times - three months' interest is the maximum a lender can charge. This is not then a "closed" mortgage. In a truly closed situation, your current lenders may dig in their heels and refuse to allow you to transfer, at least for a reasonable penalty. Depending upon your reason for wanting to break the mortgage (usually a longer term fixed rate mortgage), there may or may not be an easy solution. Let's look at the several possibilities:
 

"Blend and Extend" your Current Mortgage

You may want to break your current mortgage and switch to a new lender who's offering you a great rate, but your current lender won't let you out of your closed mortgage. This may be your only alternative, but the deal may not look ideal.

Selling your Home and Not Repurchasing

This is a tricky situation, but most lenders have an approach to solving it.