When Elaine keeps being mistakenly called 'Susie' at work, never corrects it, it gets out of control and now her boss Peterman thinks Susie is real and calls a meeting with Elaine and Susie so Elaine ends up announcing Susie has 'died'.
PETERMAN: Elaine, I'm going to start a charitable foundation in Susie's honour and, as Susie's best friend, I want you to be involved.
ELAINE: But Mr. Peterman. (whispers) I'm Susie. She's me.
PETERMAN: (leans in, whispers) I feel the same way...