Okay kiddo, let's imagine you are part of a group of friends who all share their toys with each other. One day, you decide that you don't want to share your toys anymore and you want to play by yourself. You might need to talk to your friends and tell them you're leaving the group, but it's not as easy as just walking away.
Similarly, some countries in Europe share a special kind of money called the euro. It helps them buy things from each other and makes it easier to travel between countries. However, sometimes a country might want to leave this group of euro countries and have their own money again. This is called "withdrawing from the eurozone."
But it's not as simple as just printing new money. The country would need to talk to the other euro countries and work out lots of complicated details, like how to pay back any money they owe and how their new money will work. It can be a big change and might take a lot of time and effort.