Renumbering Atom Serial

["ROPÓN-PALACIOS G."]

Dear users, 

I like renumbering serial atom into chain B to start with 1 2 3 , and write file renumbering. 

My protein have two segments A y B and and I want the serial of the atoms of segment B to start at 1 like this consecutively. Because originally this continues the serial of segment A

Best, 

geo.