In theory, there can be no etiquette differences between adult children and their parents.

As the parents presumably taught these people whatever manners they have, and the child-rearing period has been completed, everyone in a grown-up family should have nearly identical manners. Whatever slight differences children may have acquired from living on their own should be easily suspended under the general mandate of respect for the parental roof.

Surely that makes sense to all, young and old.

Miss Manners should therefore not have to worry that the Christmas return to the family homestead will entail any behavioral conflicts. She shouldn't have to worry about Christmas shopping, either, because Santa Claus will do it.

However, Miss Manners is old enough to have heard rumors that some things are not as true as they ought to be. There do occasionally seem to be etiquette problems when the happy family gathers again under the parental roof.

Miss Manners has traced them to the following wonders of nature:

The children feel they are grown up and should be treated differently.

The children forget they are grown up and don't act accordingly.

The children have changed their ways of behavior and the parents don't like it.

The parents have changed their ways of behavior, and the children don't like it.

Other people with other ideas have joined the family.

Let us see what we can do about these curious developments.

It is a common delusion among recently grown-up children that they are at least the equals of people who are apt to be shorter than they and who have not kept up with the literature (any literature -- this refers to whatever the child has just learned that he can catch the parent on).

Later in life, say about 45, they will forget why they scorned being called Sweetums and rejected offers to kiss it and make it better. But they may never get over feeling they are too old to be brought up, whether it has to do with reminders of previously taught lessons, or new advice.

Miss Manners agrees that the opportunity for child-rearing has passed, although the desire to explain to your child how to live his life never does. She urges restraint on both sides. A grown-up child should be old enough to understand that accepting advice graciously is quite a different thing from following it.

The situation is reversed when the parent wonders why the much-vaunted independence does not extend to cleaning up after oneself, let alone sharing in communal tasks. Well, it should. The last legitimate child-rearing command is "Darling, I think you're old enough to do that for yourself now."

The adult family rule is that the person whose house it is gets to set the household standards. This means that children do not try to change the routine of their parents, and in fact must go along with it as long as they are visiting. But this also means that parents visiting their children's homes must do the same. Miss Manners promises that it is worth it.

It requires not a little tolerance on the part of parents who observe their children setting different patterns of behavior, and even bringing up their children to different standards. But it also means that children cannot complain that the parents should also make those changes, or interfere with the parents' own changes, including moving to a place with no storage space for high-school trophies. Miss Manners promises that this exchange is worth it on both sides.

But what about all those other people -- spouses, candidates for spousehood, and children? They may not even start from the same basis on which to disagree.

They, too, must go along with prevailing household standards, but if the resident parents have to explain to them what these are, all sorts of objections could be raised about interfering. It is therefore up to the child who brought them to explain what is required.

He is allowed to reassure them with such soothing statements as "I know, but this is the way we eat at Grandma's house" and "Honey, it's only three more days."

For years I have been buying lovely Christmas cards engraved with my husband's name and mine. My darling husband (older than me) died last year, so I didn't send any cards last Christmas.

I have a few cards left from previous years, and I would like to use them. I would not like to cross off "and Bill." If I use them, I would leave Bill on, because our dear friends would know that he was looking down from heaven and wishing everyone well.

This is not the first time Miss Manners has had the sad task of informing the bereaved that retaining social conventions as if the deceased were alive is not the way to invoke that person's spirit in the minds of others.

Unfortunately, the reaction of anyone who sees such a card will not be "How nice to hear from Bill" but "Bill? I thought he was dead."

Crossing off his name is not pleasant, either. It suggests the opposite of what you intend, as if you had easily crossed off his existence.

The way to accomplish what you wish is exactly the way you did it in writing to Miss Manners. Have your own name engraved on new cards, or better yet just sign your name on some, and add something like, "I know Bill would wish you well, too."