Some or All of My Co-workers/Colleagues Are Missing From My Rep Drop Down Lists
If your co-worker/colleague is in the system but you do not have access to them in your dropdown lists you may be sharing an assigned region/group. This is easily fixed once we know what region is missing from your profile and get permission to add it.
Because co-workers/colleagues records map with accounts (which gives you the ability to share orders), there is a complexity there that makes it necessary that users do not create them on their own.