For what reasons might a dictatorship change to a democracy?

To create an illusion that the people have some control over what is happening in government.

Explanation:

In a democracy the government has less control over how people spend their time and what they believe. People are free to join clubs, political parties and other groups. In a dictatorship there's just one leader who has total control over the party and the country.

Dictators usually resort to force or fraud to gain despotic political power, which they maintain through the use of intimidation, terror, and the suppression of basic civil liberties. They may also employ techniques of mass propaganda in order to sustain their public support.