I have a 6ku fixie, 49cm frame. There is not much clearance between the top tube and me. So I wanted to buy the 47cm and change all the parts on that one, instead of purchasing a whole new bike. Is that possible? I'm guessing it is, because it will be the 6ku just a smaller frame. I ride the 49cm okay, but I know it would be more comfortable if it was a 47cm.
Just had a quick look at their site, there doesn't appear to be anything too special about these that'd cause problems.
However, it doesn't look like they sell frames on their own.
If you're changing to a frame from another brand then you'll have to make sure the following things are the same.
Other than that, most things should be ok. There's no guarantees though.
However, the easiest way to sort this out would be to sell this one to someone taller and buy yourself another in the correct size.
Buying bikes whole is always much better value and you're not going to have to buy a hundred new specialist tools to get the job done.
You may have issues with toe overlap, especially with a fixed gear.
The smaller frame will mean your cranks are closer to the front wheel, so your toes could touch the tyre when you turn tightly. And with a fixed gear, the pedals are turning all of the time, so more chance of this happening. Its debatable as to whether toe overlap is a problem or not - some people find it annoying or dangerous, others soon get used to it.
It will depend on the frame geometry as to how much difference a smaller frame makes to toe overlap. You can reduce toe overlap by changing to shorter cranks, which may suit you better if you are not very tall. Also narrower tyres would give more clearance.