You have a User Name that is required at login but Darzin also has a Display Name option. This name appears in the Audit trail, in "Assigned To" dropdowns and in the "created by" and "modified by" information on each edit page. By default, the names are the same but you can change your Display Name anytime.
Go to Client Rewards page and edit your contact details.
A popup will appear. The name in the greyed box is your User Name and cannot be changed. The name in the green highlighted box is your Display Name. Edit it here and Save.
Your Display Name will now appear like this ...