Marriott Corp.'s Executive World Travel, the agency that first exposed the National Broadcasting Co. expense account scandal, has been sold to Ask Mr. Foster Travel Service. The price wasn't disclosed.

Ask Mr. Foster plans to maintain its three offices in the District and will take over three from Marriott. Ask Mr. Foster is a subsidiary of First Travel Corp. of Van Nuys, Calif. It operates more than 100 travel agencies across the country.

Its chairman, John Ueberroth, stated, "The acquisition makes a great deal of sense in line with our growth and expansion plans. It will immediately give us the strongest base in the D.C. market that we've been seeking."

A Marriott spokesman said the company chose to eliminate its travel service, founded in 1971, because it didn't have sufficient potential and because Marriott didn't want other travel agencies to think Marriott was competing with them by booking customers into its hotels, cruise ships and theme parks.

The spokesman, Roger Connor, denied the sale had anything to do with the NBC scandal that thus far has resulted in the departure of about 40 unit managers from the network. Some NBC unit managers -- who traveled around the world with correspondents and crews, paying their expenses in cash -- allegedly misspent as much as $1 million. Two former employes already have pleaded guilty to fraud charges.

The fraud came to light last fall when NBC got a tip that some unit managers were diverting company airline tickets for personal use.

Last week, Carlyle Robinson, a unit manager based in Washington, pleaded guilty to a single charge of mail fraud involving the pilfering of about $5,000 in tickets.

Last March, another employe, John Cox, pleaded guilty to diverting $4,800. He was fined $1,000 and put on probation. At least two other former Washington employes reportedly are plea bargaining.