Short of calling Comcast Support I am not sure where to ask this question.
We own the smallest IPv6 allocation available - a /48 - from ARIN. We also have an ASN though honestly we do not need to do BGP. Basically we just need someone to announce the /48 globally for us.
We have two different ISPs in our data center colocation and I have no doubt the other ISP - a much smaller regional outfit that provides the colo - could do it but I'd prefer doing it via Comcast if possible, though if it comes down to it I can certainly pursue it with the local ISP.
What would be the process to do this? Is there a best contact point for Comcast support to pursue this option?