How to make allergens risk assessment if our product already allergens?
What should I do for the assessment?
Presumably answer those clauses within section 5.3 (.1-8) et al where risk assessment requirements are specified.
If yr query referred specifically to a hazard analysis a popular answer could be to define yr allergen management program as a PRP (eg BRC clause 2.2.1) and include allergen labelling declaration as a control measure. (section 10 in iso22002-1 has useful generic guidance). If you would like to see an example haccp layout can try the excel here -