Process for regaining Integration Key admin access after departure of original account admin

We maintain a demo/sandbox DocuSign account for API development, which we use to test and validate functionality ahead of deploying it against production integration keys. The original administrator who configured the account has since left the organization, and administrative access (including the ability to view/modify Integration Key settings such as PKCE enforcement) doesn’t appear to have been transitioned to another team member before departure.

We're looking for guidance on the correct process to:

1. Identify the current account owner/administrator on record for the account
2. Regain administrative access or have admin rights reassigned to an authorized current employee
3. Confirm the appropriate internal contact (e.g. Customer Success Manager, Account Executive) for enterprise accounts facing this kind of access transition

Any pointers on the fastest path through official channels would be appreciated, since this is currently blocking a required security configuration change on the integration key.

Thanks all.