Re-branding ceramic tea/coffee mugs I have been given a set of unused standard straight-sided coffee mugs with an out-of-date brand on them. 
The branding appears to have been screen-printed on then fired, so its impossible to remove (It's made from glaze)

I want to either cover this up with another brand or remove it. 
the new finish must be dishwasher safe, or removable (a sleeve?)

Is this possible? What with?
If you have a vinyl cutter, or are patient enough and talented enough to manually cut out your new brand from adhesive vinyl, there are several which are both dish-washer and food safe.  

There are also dish-washer safe acrylic paints but I don't know how food safe they are.