I'm no lawyer, and this isn't legal or investing advice.Letter to tenants of one year on a month to month agreement: Notice of Change in Terms of Tenancy (Rent)This is an Amendment to the rental agreement dated [original agreement date] (“the Agreement”) between [your name] (“Landlord” or “I”) and [tenants' names] (“Tenants” or “you”) regarding the property located at [address] (“the Premises”).As per our month ­to ­month Agreement, your rent will not be increased until April 1, 2016. 

When the lease expires, if you want to keep her, I would amend it.

The link below goes to the PA Landlord Tenant Act of 1951.https://www.thelpa.com/PA_landlord_tenant_act.pdfI believe this is the current act, but check for amendments.

Consider changing your lease in the future, or now with an amendment, to include the use of the laundry room with the rent.

or should I amend with a tenant removal and add the new co-signer/co-tenant onto the lease?

If the lease doesn't provide for it, you can't legally charge them a late fee.You can, of course, have this woman sign a new lease (or amendments) at any time, but she is not required to.I agree with most here that she is not a good tenant if she is paying late.  

If permits were not pulled/ there is not an amended certificate of occupancy, the systematic code enforcement inspectors will almost certainly order the units converted back OR require permits to be pulled and proof that the conversion was done to code (assuming that is even possible).Additionally, under rent control, you will then need to credit the existing tenant for the loss of the amenity that occurred when they lost a bedroom.Proceed with extreme caution as SCEP inspectors do not mess around . . . 

Amended by Acts 1985, 69th Leg., ch. 305, Sec. 2, eff.

I also am wondering what I need to do to amend the rental agreement to include him.SF bay area/$1,300 mo. ~ water and garbage paid by me.Thanks in advance.

If not, then amend the rental agreement/lease for the addition of another occupant.