Q. We have just purchased a big, beautiful old house, and we would like to name it. There is just one problem--we don't know how!

What is the ceremony for the christening of a house? Do you hit it with a champagne bottle? Pour holy water on it? What? Please help us!

A. No, no--that's a baby you hit with a champagne bottle, and when you have a new ship, you sink it in holy water.

No, that's not it, either. Please forgive Miss Manners. She gets so excited at the opportunity to invent a new folk tradition that she tends to babble a bit.

An invention is called for here, because there is no national tradition for christening a house (although if there are regional ones that have escaped her attention, she would be glad to hear of them).

We shall start, of course, with the basic housewarming party, long associated with moving into new quarters. This is generally a late afternoon cocktail party, to which friends and neighbors are invited, usually in family groups, and allowed more or less the run of the house, which they are supposed to admire, at least until they get home.

Suppose you make a banner with the name of the house on it, and put it up over the front door--or put it up covered, and then dramatically reveal it, after you have led your guests outdoors for the ceremony. You could then break out the champagne (break out, not break over anything).

Miss Manners hopes she need not tell you that the banner is to be removed after the party. Even if you are living on a vast estate with ancient associations, but especially if you have named your town house "Palazzo Venezia," you must always use the name in an affectionate, joking way, as you would if you had named your car "Roamer."

Copyright (c) 1983, United Feature Syndicate, Inc.