apikey

I have access to three Sub Account.
I can create package inside any of the sub accounts in UI.

If i create a package through API it will be created inside my home sub account

How to create package in different sub account using API for a particular user as sender

How can I pull the subaccount user's apikey using parent account's apikey? I have called api/senders/{accountid}/apiKey and it returns 403. The same method works for the main account however. In other words, I can pull apiKey from other senders using the owner's apiKey on the main level but couldn't do the same for the subaccount. I would appreciate any help that can be provided.