It’s not possible for resellers to utilize the transfer tools that are available to the root user. There’s a feature request open for this at:
There is a very explicit reason why this feature is not in the product. Allowing non-root users to restore accounts is a significant security concern.
The current restoration system expects and anticipates that only the root user will request a restore, meaning that it trusts the information within the backup to be what the root user wants to restore. If this were extended to resellers, then a reseller would be able to restore an account with any custom features they wanted (unlimited bandwidth, unlimited disk space, etc)
It is the current design and expectation that only the root user restore accounts and that they’ve verified the account is of acceptable limits/configuration post-restore.
In essence, this feature request is presently not realistic without also redesigning the entire restore system from the ground up. Even then, significant research would still need to be conducted on whether or not this would still be realistic from a security standpoint. There would be many configuration portions of the restore process that you could not and simply would not want to entrust a non-root user to be able to set upon restore for security reasons.