Sorry for the misinformation.  There is an FCC (PDF) document somewhere I will find, that has January 23 as the date of WIVB's RF 39 signoff, plus this from the FCC release DA 17-314 Released: April 13, 2017

3. Channel Sharing Stations
76. A channel sharing station (113) must implement shared channel operations, and a sharee
station must discontinue operations on its pre-auction channel, within 180 days after the sharee receives its share of auction proceeds.  114

Also, was told from someone at the FCC (as I posted earlier somewhere) that a station is considered to have received payment 5 business days after the release of the documents.
[Link: transition.fcc.gov]

Sorry...