Dear Miss Manners: I have a good male friend who I once shared a house with (platonically) for six months. He is pleasant company, has provided me with good advice, is extremely considerate and has helped me run errands on several occasions. I value his friendship and have no wish to offend him.

However, I am now living with my boyfriend, and it is only a matter of time before my good friend’s previously charming habit of dropping by unannounced to say hello results in deep embarrassment on all parts.

If he continues to drop by unexpectedly of an evening (with no warning or pattern), inevitably he will one day find my boyfriend and me preoccupied, not sufficiently dressed to receive visitors, or simply in the middle of an argument.

How do I ask this good friend to call me by telephone before coming around, without causing offense or implying that I don’t value his friendship? He is very shy and proper and would be embarrassed, shocked and offended to accidentally intrude on any private moments between my boyfriend and me.

Gentle Reader: We’ll get to that in a moment. First, is he using the house key he had when he lived there?

If so, change the lock without explaining. Should he ask, do not apologize, but say vaguely that it was a matter of security. Above all, do not offer to supply him with a new key.

If that is not the problem, Miss Manners would like to address your habit of opening the door while otherwise preoccupied, insufficiently dressed and in the middle of an argument.

Unless a visitor is there to warn you the building is on fire, or shows signs of being in immediate distress, do not answer the door under such circumstances. You need not be “at home” to visitors as long as you can resist the temptation to peek through the curtains.

When your friend brings it up later, say you are so sorry you missed him. If he were to give you warning next time that he is coming by, you will be sure to listen for the doorbell.

Many happy returns

Dear Miss Manners: I received two gifts that included gift receipts. After thanking the donors, I returned the items because they were not to my liking. Having gift receipts made the process easy and possible.

One donor asked if I enjoyed the item and was disappointed to learn that it had been returned. What should one do if the situation repeats itself?

Gentle Reader: Tell the donor that you enjoyed the item, as of course you did. Miss Manners sees no reason to explain that your enjoyment came from being able to turn it into something that you wanted.

This column was co-written by Judith Martin’s son, Nicholas Ivor Martin.