Respect your elders.
"Yes, sir."
"I'm not your Professor anymore, Lily. You may call me Albus. Everyone else does; even James." He smiled warmly at her now that their brief Order meeting was over (she was always the last to leave), eyes twinkling from behind half-moon glasses.
"I know." She toyed with the edge of her robes as she rose gracefully to her feet. "It just feels wrong – too informal somehow." Really 'Sir' was more of an endearment than a title and she enjoyed the intimacy that came with it. That she was the only one to still address him as such just made it all the more special between them.
"Very well. I shall see you next week. Take care, Lily." He stood to hug her and she sunk into his familiar embrace, even pressing a kiss to his cheek.
"Take care, sir."
After she had apparated with a crack, Albus shook his head with a smile.
She was just as he had imagined a granddaughter of his own might be.