If your plan is to replace the the S2 with the S3 and still have only one Tivo then yes, you can and there are two ways to do it.
Option 1. Cancel the sub on the S2 and start a new subscription and commit to three years of service to get the $12.95/mo rate.
Option 2. Transfer the service from the S2 to the S3. The easiest way to do this is online at tivo.com. Just go to "manage my account" and sign in. Then choose "change service number" (from the menu on the left). Then you indicate the TSN of the The S2 and enter the TSN of the S3 then click on the "Change" button.
About any rebate - you can't get a rebate if you choose option #2. Rebates have to be on new subscriptions. A new subscription will require you to commit to 1, 2 or 3 years of service. Transfering service from one tivo to another is NOT a new subscription. Choosing option #1 is the only way to get the $12.95/mo rate and a rebate. If you get a Tivo HD rather than the S3, there is no rebate at this time, so option #2 would be the better option
Option 1. Cancel the sub on the S2 and start a new subscription and commit to three years of service to get the $12.95/mo rate.
Option 2. Transfer the service from the S2 to the S3. The easiest way to do this is online at tivo.com. Just go to "manage my account" and sign in. Then choose "change service number" (from the menu on the left). Then you indicate the TSN of the The S2 and enter the TSN of the S3 then click on the "Change" button.
About any rebate - you can't get a rebate if you choose option #2. Rebates have to be on new subscriptions. A new subscription will require you to commit to 1, 2 or 3 years of service. Transfering service from one tivo to another is NOT a new subscription. Choosing option #1 is the only way to get the $12.95/mo rate and a rebate. If you get a Tivo HD rather than the S3, there is no rebate at this time, so option #2 would be the better option