What to honor for changed rent ad?

[Kadia Lawrence]

Hello,

I am wondering how this would work. Are there rules, particularly in Pittsburgh, PA, around what you must honor for prospective applicants if you change your rental rates and concessions? If for example you reduce the rent and remove a concession (e.g., last month's rent free)), and someone starts an application at the old advertised higher rental rate + concession but then completes the application after the change (lower rate and no concession), is there a rule for which you must honor?  If people are notified of the change before they complete their application and still opt to complete it, does that make a difference?