DEAR ABBY: I’m scheduled to go on a vacation with my mother and sister. It seemed like a fun idea during the planning, but as the date approaches, I realize it might not be possible for my sister and me to get along and remain civil during the trip.

We are in our mid-to-late 20s now, and I was hoping we had matured enough to handle our differences calmly. Recent events, however, have proven otherwise. Our relationship has deteriorated to the point that she’s triggered by anything I say or do, and it’s impossible to talk to her.

We’ve never had much in common, and our personalities are like oil and water. I’m thinking about backing out, even though I was looking forward to visiting New England and seeing my favorite singer in concert. I don’t usually take time off from work, and I don’t want to risk wasting vacation days possibly being miserable walking on eggshells. I know arguing with her will lead to nothing productive. How can I handle the situation differently? — FINISHED SISTER IN NEW YORK

DEAR SISTER: You stated that you were hoping that you and your sister had matured enough to manage a vacation together in spite of your differences. Rather than back out at the last minute, why not choose to be the more mature sister and simply not argue with her? That way you can see New England and enjoy your favorite singer in concert. You do not have to spend every spare moment with her; you are not joined at the hip.

If the trip proves to be unpleasant, agree to join your mother and sister under only limited circumstances — perhaps at breakfast or a dinner — in order to keep peace in the family.

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Dear Abby is written by Abigail Van Buren, also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Contact Dear Abby at www.DearAbby.com or P.O. Box 69440, Los Angeles, CA 90069.