It looks like that mod does not have a rebuildable atomizer option. So, for the easiest way to change flavors, without having a dozen little baggies with used atomizer heads for each flavor all over your desk.. I would wait until your tank is empty or nearly empty, remove the tank, rinse with warm water, you can use regular dish soap if you want, but rinse well to get any soap out. JUST rinse the tank, not the atomizer head. Shake out excess water, blow out any you can by blowing through the mouth piece with the tank off the mod. Don't worry if there is a speck of water inside, it won't make a difference.
Put the tank back on the leaving the atomizer in place. Turn the wattage (power) down as low as you can while still getting vapor, and vape it until it tastes "cottony". You'll know when you taste it.. kind of like how the cotton your dentist uses tastes. The low power is so you only burn off the juice in the wick, without burning the actual wick. Once you get the cottony taste, just fill with the new flavor. There will be a slight taste of the old flavor, which you probably won't even notice anyway.
I use this method when changing flavors sometimes, usually I just add the new flavor to the empty tank, and don't bother with the rinsing.
Unfortunately, the link to your mod was removed in the original post, so I had to actually google the mod you had. It's hard to give advice on how to or what to do, if you don't know what the poster has to work with.
