Cass would most likely not have noticed the tiny butterfly if it hadn't started to speak to him - with Pansy's voice, but by the time it was finished, he'd had the longest laugh in quite some time.
Calling for the Auror office house elf, he told the elf to go and open the door, ignoring the slight mutterings (Opening doors. Not even and Auror anymore. Unimportant tasks. Will not be made normal house elf. Am more important than that.) of the elf as he wandered down the stairs and opened the door.
'This way Miss,' he said formally, turning in the door and muttered under his breath all the way upstairs as well, finally showing her into the bedroom where Cass was still confined.
'You can go back to the office again, thank you,' Cass said after the elf, who disappeared so quickly he probably only heard half of it and kept muttering about never being thanked for the meaningless tasks he was made to do for the non-Auror. Cass refrained from rolling his eyes as he smiled at Pansy.
'You know, there is such a thing as knocking,' he said amused, nodding towards a chair. 'I hear it's much more common than sending patronuses to announce your arrival.'