Everything she says in public has to match up 100% with what was written in the report at the NRA 15 years ago. If she exaggerates, and it is later found that what she says now was not what she said then, she will be facing libel suit - it won’t be he-said she-said anymore.
So they probably pulled out of the conference either to see if they can find or reconstruct the documents/statements or find witnesses who can remind them of what exactly was said. This isn’t just play-time, a man’s reputation is on the line. They need to be accurate, and they need to be credible. The burden of proof is on the accuser. If it ends up sounding like this woman from today who said “well I don’t remember anything he said it just felt wrong” - sheesh!