Tenant Request to Move in Son's Family

[Dennis Hill]

Good morning BP Family,

I have leased my property to a couple who has now asked "how much would it cost us to move our son, his wife and their child in with us"?  I currently rent the property for $2,400/mo.  The property is located in MD.  My question is can I legally modify the lease to add the 2 additional adults and increase rent by $600/mo?  Appreciate any advise you all have to offer.  Thanks.