Final answer:
To handle a tip not attached to a bill, you should thank the giver and accept it graciously, ensuring you adhere to your employer's policy on accepting tips.
Step-by-step explanation:
When someone gives you a tip that isn't attached to a bill, the professional and courteous action would be to thank the giver and accept it graciously. Tips are often given to show appreciation for a service provided, and it is customary in many service industries to accept them unless there is a specific rule against it in your place of employment. If you're uncertain about the policy regarding accepting tips directly via cash or through a debit transaction not included on a bill, you should consult with your manager or employer for guidance.