With Assistant Secretary of State for European Affairs Richard Burt odds-on favorite to succeed Arthur Burns as U.S. ambassador to the Federal Republic of Germany this spring, yet another major change looms on Nancy Reagan's staff. Burt, you'll remember, married White House social secretary Gahl Hodges earlier this year.

Before the lines start forming at the East Wing gate for a job that some covet as the most desirable at the White House, would-be applicants should know that Hodges isn't yet scheduling her departure; if Burt gets the post, she may wait awhile before joining him. When she does leave, though, Burt supporters at the White House expect them to become two of the brighter lights on Bonn's diplomatic front.

The popular Burns, 81, originally planned to return to Washington in March. He later agreed to be on hand when President Reagan joins other leaders in Bonn for the annual economic summit of noncommunist industrialized nations May 2-4. The Reagans will stay on in West Germany for an official state visit May 5-6.

Secretary of State George Shultz is known to be especially high on Burt, who played a major role last week in defusing a potential controversy over Reagan's participation in the 40th anniversary of Allied victory in World War II. One source credits Burt with behind-the-scenes work that resulted in an invitation from the European Parliament to President Reagan, who will address a V-E Day ceremony in Strasbourg, France.

Shultz personally went to bat for Burt in 1983 when his State Department nomination was stalled for almost a year by conservatives in the Senate. A former New York Times reporter, Burt was in hot water for, among other things, a 1979 article he wrote about a U.S. spy satellite that could monitor Soviet missile tests.