People change the address on an account for ordinary reasons: they signed up with a personal address and want the account on the company domain, or their company changed domains, or the account should sit with a shared mailbox instead of one person.
Write to support@argorant.com from the address currently on the account and tell us the new one. Sending from the current address is the proof of ownership, which is why we ask for it rather than accepting the request from anywhere.
What moves with the change: your plan or wallet balance, your saved lists, your export history and your API keys. Nothing is reissued and no credits are lost, because the account is the same account with a different address on it.
One thing that does not move is the 25 agent starter credits. They are granted once per account and once per mailbox, and plus-addressed or dotted variants count as the same mailbox. Changing your address does not create a second entitlement, and it is not a route to a second grant.
If what you actually want is a separate account for a colleague, do not rename yours. Have them sign up in their own name, and keep API keys one per person or per integration so usage stays attributable.