From A Career Man To A Family Guy
The Character Tony Nelson was played by Larry Hagman. His character was the astronaut. While he spent every night with Jeannie, during the day he worked for the government. When the show began, writers made Tony a serious and uptight character.
Source: Wikimedia
They made him a guy that’s more focused on his career instead of focused on Jeannie. As time went on, they wrote him to be more interested in Jeannie and in fact by the end of the series they even settled down and got married! Quite a change in character but made sense for the plot.