If made correctly you should have on your lease, that if there is more people living in your unit then signed for, then the person would have to pay a fee then when the lease expires they can sign together, also please dont tell the bluntly about the rent going up make up a letter stating that with the increase cost of up keeping, takes and the like that you must increase the rent by 1 dollar a day or 2 a day which would add 30-60 dollars to the rent. good luck -Tony