No, user names cannot be changed. You will need to create another user with the preferred name and then delete the original user. Please note that if you delete a user, you will delete all of the files contained in their "Private" folder; follow these steps to make the process smoother.
1. Move all of the files that you want to keep from the "Private" folder to a "Shared" folder.
2. Go to "Users & Groups" and then click "Power users"
3. You have two options: deactivation and deletion. Deactivated users do not count against your plan's user quotas, and their files are still maintained. They can be restored at any time. A deactivated user's files still count against your plan's storage quota. Deleting a user means that their files are permanently removed.
Click on the username that you wish to remove and hit "Deactivate" or "Delete" in order to deactivate or delete the user respectively. If the user is an admin, you need to have a secondary admin in your Egnyte account and you will need to demote the account from an admin to a power user. You can then delete or deactivate the previous admin.
4. Create a new username of your choice by clicking on "Add Power user."
5. You can then move the private data that you moved under "Shared" into the Private folder for the new username.
If you use Desktop Sync, the client will have to be uninstalled and reinstalled to change the username. However, you may use the same Local Cloud directory so that synchronization does not start from scratch.