How do I give two people access to the same form, one after the other - for a performance appraisal?

I am developing a performance appraisal using Qualtrics. I have it set up and working for the employee's self-assessment. Once that is complete, I would like to forward the self-assessment to the employee's supervisor for the supervisor to add their assessment of the employee's performance to the same form.
How can I do that?
The scores for each will probably be different but I will want to record both for future reference.
Thank you for any help you can give me!