If the person is the "head of household" you cannot do it. 

The one exception is that if a PHA issues 1 Bedroom rate vouchers to 1 person households, they may elect at some point to move those vouchers to studio rate vouchers (0 bedroom rate), which could serious impact the rate that new tenants could rent at, but again would not change the total amount of rent collected by you for tenants currently under a rental agreement.

If they meet your minimum criteria to rent, change the lease agreement with the signatures of all parties involved to reflect the new household make up.

Everyone who will be living in the household who is 18 years or older.The more people on the lease, the better chance you have of collecting your money!

If the remaining party requests to add a new person to the household, the new person must qualify.

If the one paying the rent is legal the entire household may be not.

On going, every November we give a grocery store gift card to each household one week prior to Thanksgiving. ($10)For our 8-plex apartment community, we established an area where tenants could garden.  

The lady asked if the minimum salary was for an individual or household.

If you charge a higher rent because of the change in the make up of the household, you may find yourself in violation of fair housing laws.

Every household can function without them just fine!