K.
One suggestion is to ask Megan's mom if there is a reason why Megan doesn't want to be her friend anymore. This happened to my daughter now 9. She was in a different classroom and the only time she saw her old best friend was on the playground. She spent the rest of the day buddying up with the girls in her classroom. We invited the friend over for dinner one night after school and they were best friends again. They even wanted to buy best friend outfits that they would wear to school on the same day. Also my daughter wears glasses and I let her place washable glitter glue on the frames to make them sparkle on day. This went over really well. She was the only one in her grade to have "sparkle" glasses.
You might also suggest that she doesn't have just 1 "best friend".