If you wish to cancel your Yahoo! Phone Out account, no action is necessary. Once you use up the funds in your account, if you do not recharge, your account will no longer have funds available. If you want to use the service again, you can add funds at any time.
Please note that if you have the auto recharge turned on, you will have to turn it off to prevent any recharge to your account when the funds fall below $2.00. If you do not wish to have your account stay active so that you can add funds at anytime, please contact customer support.