No, it’s not. To change the type or the base currency of the account, you have to open a new account with required parameters.
Demo accounts are usually used in three cases: If you are a beginner and want to learn basics of trading on financial markets without risking to lose your own money. When you want to test the conditions provided by the brokerage company before opening a real account. In case of testing your new trading strategy.
“Not enough money” means that there is not enough margin on your account to open a position of the desired volume.