Change the Incident Reference Number

To change the incident reference number (a.k.a the incident identifier or incident number) go to incident administration in the admin view.

Incident Administration 

Go to incidents and select the incident you wish to edit.

Switch from Overview to Administer

You are currently viewing the incident, switch to administering it by pressing "Admin".

Administer an Incident

Scroll down to the incident reference and tap "Edit Reference".

Edit and Update

Make the required change and the tap "Update Incident"