Here's the official announcement from the Phillies press release:
The May 3 Phillies vs. New York Mets game, which was postponed due to inclement weather, has been rescheduled as part of a day-night separate admission doubleheader on Sunday, September 13 at 8:05 p.m.
Fans holding tickets for the May 3 game can use those tickets for the rescheduled game at 8:05 p.m. on September 13.
The regularly scheduled game on September 13 will begin at 1:05 p.m. Fans holding tickets for September 13 should attend the 1:05 p.m. game.
The 1:05 p.m. game will be televised locally on myphl17. The Charlie Manuel Show and W.B. Mason Behind the Pinstripes will air on myphl17 at noon and 12:30 p.m., respectively. Broadcast information for the 8:05 p.m. game will be announced at a later date. In addition, the games will air on WPHT, The Big Talker 1210 AM, and the Phillies' Spanish Beisbol Network on WUBA (1480 AM).