She wanted time to gather her wits for meeting Barney.

When Miss Grierson told her that her cousin was still waiting to take her to dinner, she requested her companion to inform Barney that she would be in as soon as she had dressed.

She wasted all the time she legitimately could in changing into a dinner-gown, and when at length she stepped into her sitting-room she was to Barney's eye the same cool Maggie as always.
Barney rose as she entered.

He was in smart dinner jacket; these days Barney was wearing the smartest of everything that money could secure.
There was a shadow of impatience on his face, but it was instantly dissipated by Maggie's self-composed, direct-eyed beauty.
"How'd you come out with Miss Sherwood ?" he whispered eagerly.
"Well enough for her to kiss me good-bye, and beg me to come again." "I've got to hand it to you, Maggie! You're sure some swell actress--you've sure got class!" His dark eyes gleamed on her with half a dozen pleasures: admiration of what she was in herself--admiration of what she had just achieved--anticipation of results, many results--anticipation of what she was later to mean to him in a personal way.

"If you can put it over on a swell like Miss Sherwood, you can put it over on any one!" He exulted.