Wash DC return with some PA income & tax

[HV Ken]

** Never mind - finally found it! **

I have a client who lives in and works in Washington DC. He went on assignment for one month to Philadelphia, so he has a 2nd W-2 from that. Is there a place on the DC return where he can subtract the tax paid to PA so he is not double taxed on the income? I have been searching the DC Office of Tax and Revenue web site, but cannot find it, if it exists.

Thanks!