If someone owes you money and you need it, you approach him and remind him of his debt. How do you call this act? a) Peter needs to see Mike to collect the money that he owed? How about if you are the tenant and you need to collect rent fees from people who are renting your apartment? b) Mr. Smith will return tomorrow to collect the rent? I'm not sure if my sentences are correct or if they are formal. Please give expressions in both registers (formal and colloquial) and the ones that sound natural. Thanks.