Take ownership of helpdesk (Applications Template) work order

We have  a sharepoitn system which is using the helpdesk workorder template. It all works great, but for the following scenario.

A user emails us directly, we then create a work order FOR them, logging in under one of our helpdesk accounts. The user cannot then add comments to the workorder as they did not create it.

I am wondering how you would go about changing the ownership? I have tried giving them permissions on the site but they still cannot edit. And obviously, that is not ideal as then they could edit any one elses work orders as well.

Is there any way to change the owner, the "created by" tag seems to indicate?

thanks.