A Rose By Any Other Name . . .
People can have all kinds of reasons to use another name, or to change their names permanently, for that matter. There are personal or family reasons, like marriage or adoption. There are political or social reasons, like marking a religious conversion, or immigration – though that last’s not as common now as it was in the early to mid-20th century. My own father, for example, changed his name to Malan because British authorities – to whom he had to report regularly as a displaced person after WWII – suggested that he try to sound less Polish since he was planning to stay in England. He chose a name much in the news at that time, and that’s why my brother and I are often asked if we’re South African.
Setting these examples aside, however, actors and writers are probably the next large group of people who frequently change their names – or at least use other names as a pseudonym, or nom-de-plume, if you prefer. (A friend of mine once referred to her real name as her nom-de-nom.)