Okay, kiddo. So you know how there's a game called football and there are teams that play against each other in the National Football League or NFL? Well, sometimes those teams move to a different city or join with another team to make a new team.
Let's say the team in your city, we'll call them the Lions, wants to move to a different city. They would have to ask permission from the big people in charge of the NFL, called the owners. The owners would decide if the Lions can move or not.
If the owners say yes, the Lions would have to find a new city to play in but they would still be called the Lions. This is called franchise moves.
Now let's say two teams, the Giants and the Jets, decide to join together and make one big team. They would have to agree on a new name and where they will play their home games. This is called a merger.
So sometimes teams move to different cities or join together to make a new team, but they have to ask for permission first and sometimes change their name. It's like if you wanted to move to a different house, you would have to ask your parents first and maybe change your address. But don't worry, football is still fun no matter where the teams play or what their names are!