If the flavors are similar, you can just add it to your clearo and they will blend. Next refill, it will be all the new flavor. Sometimes mixing a couple flavors in one tank is fun to try too. For very different flavors, a quick hot water rinse and shaking it our well should be all you need to do. No need to wait to dry it, just blow the moisture out, wipe it off well and fill it. You should expect the first dozen pulls to be weak as the residual water vaporizes out of the wick, then you're on your way!
Some flavors, like watermelon and coffee, are really persistent, and would be best used in dedicated clearos, or if the head is replaceable, dedicated heads. Once you have accumulated a little more vaping equipment, you may want to have a couple clearos or tanks filled with your favorite flavors, ready to swap.