Writers and Approvers can be changed at a Section level or a Question level.
If you are the only User, you will need to add a New User [see Add a User] button to the right of UPDATE ASSIGNMENTS.
This screen will appear, you can send it to multiple contacts if needed:
A Team Member* will also be able to answer on your behalf if you have set their toggle from the Dashboard page to Read Only [NO], be sure to press the [SAVE] button after toggling YES or NO. Access this through Discovery Dashboard > Project Details > TEAM MEMBERS
*However, Team Members will not come up in your options for Writer or Approver drop-down for a workflow, they can come in and write/approve for you.