If the person has a sudden onset of illness with changes to airway and/or breathing and/or circulation and usually with skin changes:
Call for help
Lie the person flat and raise their legs
Adrenaline is the urgent treatment which should be given. An anaphylaxis pack contains the equipment you need including Adrenaline autoinjectors
When help arrives, give a clear handover of the situation
Document accurately what has happened and your actions