One thing you can do is change the channel and change back, that will clear the buffer so you can record, but you need to do it early enough to catch whatever it is to record.
You can only edit the video after you download to a computer and edit with programs like VideoReDo for Windows. Rename the file and send it back to the Tivo.
Series 2 (PLS, sold)
TiVo HD 1TB (157 HD Hrs, PLS, "652")
Roamio! Oh, wait, Its Juliet!
OTA! OTA! OTA!
The TiVo Apocalypse begins on Sat 2013 Feb 16 00:00 GMT!