Hi Tom Benedict,
Thank you for reaching out to us on the Microsoft Q&A forum.
To switch your startup sponsorship to a different Azure profile, you have two options: you can either transfer your sponsorship credits to the account associated with your pay-as-you-go subscription, or request to migrate your subscription to the account holding the sponsorship credits. While it is possible to switch credits to another Azure account, please note that this process is not available as a self-service option. Instead, it requires assistance from a billing engineer to ensure the credits are properly assigned. To proceed, we kindly ask you to create a support ticket so that the appropriate team can assist you with this request.
Please reach out to us if you have any other queries.
If the information is helpful, please Accept Answer & Upvote so that it would be helpful to other community members.