If you really want to do this in a way that is permanent then try the following:
First, Whink off the design (Whink is a rust remover available at most large grocery stores. The technique is rather slow (12 - 20 minutes) but it will remove the flowers. (This is only for paint that is under the glaze.)
1. Place a viva paper towel over the part that you wish to remove. (Do a 3" area at a time)
2. Wet the paper towel with the Whink and make sure that there are no air holes in the paper towel. Leave for 20 minutes and peek and see if it's gone. If it is, then wash with water. If not, then check after 10 more minutes. It must stay wet. (Do this over lots of newpapers or a plastic surface) This will work on painted plates, tiles, decals, etc.
Warning: this is an acid and be sure and use heavy diswashing gloves. Also rinse the sink well after rinsing off the article. The water will nutralize it, but it's still not enviornmentally friendly enough where I would use it outdoors under any circumstances. The sink is fine if you make sure that it is all washed away. If it gets on your skin then wash away quickly...I have had it on my skin for more than 10 minutes but it does and will cause burns if under fingernails etc.
To repaint it professionally, use overglaze paints and fire it to cone .017
To see an examples of overglaze painting , then go to my website at:
For more information about painting pottery or ceramics or porcelains, then go to ppio.com.
Otherwise, I LOVE the suggestions on using the acrylic paint, etc. They are darling! I probably gave you more info than you wanted to know about fixing it professionally but just in case anyone ever did really want to 'erase' a design, then this is here for their information as well.
Good luck, and I hope that you have already painted it and it's wonderful looking.