user65200: Does anyone know what free bitcoin wallet can support the cancellation of unconfirmed transactions? 

user61384: Yes. Most software wallets will have this feature. It's called double spending with a higher fee.
There is not really a thing as "cancelling" a transaction, once it is broadcasted, it is unstoppable, unless you double-spend it. (The first tx will get cancelled)

65200: <p>Does anyone know what free bitcoin wallet can support the cancellation of unconfirmed transactions? </p>
 61384: <p>Yes. Most software wallets will have this feature. It's called double spending with a higher fee.</p>

<p>There is not really a thing as "cancelling" a transaction, once it is broadcasted, it is unstoppable, unless you double-spend it. (The first tx will get cancelled)</p>
