[Chimera-users] Assigning id to a chain with no id

Hi, I need help with chimera. In my pdb I have a chain with no id and I want to assign it a new id. I tried using 'changechain' command but I am getting error messages because I don't have any specific from-chain id. I don't know what exactly to give as from-chain id or is there any other command that could help me? Thanks, Aleena.