56h in int 21h

[jingo1126]

guys need help says when executed.The syntax of command is incorrect.. i dont where i went wrong..here is my code..

.model small
.stack 100h
.data
file   db   "TEST.TXT",0   ; File name
new   db   "Rename.txt",0   ; New name
dir  db "D:",0 ;Current directory
.code
start:
mov ax,seg dir
mov ds,ax 
mov dx, offset dir
mov ah,3Bh
int 21h
rename:
   mov   ah,56h      ; open file read/write
   lea   dx,file      ; points to file name
   lea   di,new      ; renames to
   
 

   int   21h	
   
end start