Town Enalargement query

I was wondering if it was possible to enlarge a town from 100x100 to 200x200 (using the existing town as the centre point (i.e. extending each side by 50) and if so what application should I look at posting?
Apologies if this has been asked before

 

Thanks Nicit, I've just found the rules in the Wiki and it says the size cannot change, you can't argue with the rules It's a shame, there is no bordering town and if there is an additional cost to expand to the bigger size, most Mayors would take that opportunity, unless it's a software/code restriction of course