Rachel watched as the door knocked, and didn't bother with anything. She just waited, and finally got a glimpse of that neighbor.
She frowned, and walked a bit closer. She frowned as what Carly had said about the house, because Rachel hated when people messed up her opportunity to meet new people. Especially when she hadn't even gotten to know the newcomers. When she'd finally got in range of being able to be heard, her footsteps became a blur, and turned into a pretty white/blue smoke that only she, and other ghosts, could see.

She sat down on the couch about a foot away from Carly, and listened. She wanted to see how good this was. If it was really that bad, she'd just start to cry... or, if she could manage to make her VOICE invisible.
Though Iris was easily hurt, she had to keep her tears to a minimum. Sometimes her tears became real, and soaked into things. Or she cried in front of a human, and was audible.
So she just waited patiently.