What has happened in your life financially that place you in a position where you are not able to pay your rent. Apparently, when you were approved to become a tenant of the senior subsidized housing you were financially qualified.
If you are unable to pay your rent you would be given the proper signed written notice, to pay your rent or quit (move) if you are unable to pay the rent or choose not to move based on the signed written notice, your landlord would start the legal eviction procedures against you.
The legal eviction would be signed by a judge and have a date that you would be required to remove yourself and all your personal items from the rental unit. If you fail to move based on the legal eviction, a local law enforcement agent would come to your door and have you physically remove yourself and all your personal property from the rental unit.
It appears as if you are able to pay a partial amount on your rent, it would be to your benefit if you would speak to your property manager, explain the financial situation you find yourself in and the date you be able to pay the rest of your rent.
Do not surprise your landlord or property manager when the rent is due, you already know you are unable to pay your rent.
I hope this has been of some benefit to you, good luck.