This depends on if further treatment is required.
Appliance fitted only
If you've closed the original CoT as FTR, the patient has returned at a later date and you've fitted the appliance, you must withdraw the original claim and resubmit it as a band 3 treatment completed claim.
Appliance fitted and additional treatment
If you're reopening the original CoT because it was a short period since the original claim was submitted or your records are not robust for attempted contact with the patient, the further treatment would be considered to be part of the original band 3 course and no further claim should be made.
You must make the relevant amendments to the existing claim.
If the clinical notes detail the previous failed attendance and the attempts made by your practice to rebook the patient's appointment before submission of the original incomplete treatment claim or a long period has elapsed since the original claim was submitted, you're able to claim a new band 3 CoT for the fitting of the appliance and extra treatment required.