i have a 4s swap for 4..... ?

hi everyone.....i have iphone4s and i want to swap with a iphone 4....because i need some money but i dont want to use another phone because am a iphone lover:)))...on vodafone and has original box with everything.....if possible must be unlocked and in mint condition with everything...if you are interested and really serious send me a text pls...what you got????basildon or nearest pls because i cant travel....my 4s only 4 months old in mint condition...not scratch....in perfect and black 16gb one.....thanks for read.....07523223588 only text pls