Within Teamwork Projects, you can change the name of the creator of a task to another user.
To do this, select the Tasks area and then the specific task you wish you edit. When viewing the task details, click the options (three dots) button to the top right, and select Modify Properties from the dropdown menu.
You will now be presented with a box where you can select a new creator from the drop down, the names here will be the users who have the permissions to create tasks on the project.
You can then choose to Apply Changes and the creator of the task will be changes.
For more information on changing task details see: Changing the date a task was completed