Obviously " Will’t please you rise? " refers to "Will it please you rise?"
But "it" seems redundant here.
Context:
Never to stoop. Oh sir, she smiled, no doubt,
Whene’er I passed her; but who passed without
Much the same smile? This grew; I gave commands;
Then all smiles stopped together. There she stands
As if alive.
Will’t please you rise? We’ll meet
The company below, then. I repeat,
The Count your master’s known munificence
Is ample warrant that no just pretence
Of mine for dowry will be disallowed;
Though his fair daughter’s self, as I avowed
At starting, is my object. Nay, we’ll go
Together down, sir. Notice Neptune, though,
Taming a sea-horse, thought a rarity,
Which Claus of Innsbruck cast in bronze for me!
More:
http://en.wikipedia.org/wiki/My_Last_Duchess