Can the name and symbol of an already created token be changed?

This depends on the specific blockchain, as different chains have different rules:

• EVM-compatible chains (including BSC, ETH, Base, etc.): Cannot modify the token’s  name or symbol after creation.

• Solana : Can modify the token’s full name and symbol with the proper access permissions.

• TRON blockchain: Cannot modify the full name or symbol; modification is not possible.