Yes, an existing record can be updated via:
Enabling the Set as editable option will allow users to edit the values within your record (except for the Story Name and Timestamp values):
Within your tenant, navigate to the record -> Manage record.
Enable Set as editable:
Click on Save.
A pop-up window will appear, confirming your changes. Click on Confirm to apply:
Use the update records Tines API to update records.