use the alter command:
alter chain "", chain="A"
See also http://pymolwiki.org/index.php/Alter
James Starlight wrote, On 04/26/12 09:18:
Dear PyMol users!
I have some structure.pdb from the md simulation wich consist of 1 chain not defined in the pdb file explicitly ( missing chain id in the pdb file). So the pymol recognise that chain as the ' ' . I need to rename this chain to the desired name ( e.g to chain A ).
How I could do it?
MPI for Developmental Biology