pgp key size

Hi

 I have a main key that is 1024. This is being used by many clients. There is a new client that emphasizes on the main key being 2048 bits.

- Can I change the main key? Is that possible?

- If I change it, I will have to export it and send it across to ALL the clients that have my 1024 public key. Is this right?

- I can generate a subkey with 2048. But they want the main key to be 2048. what are my options?

Thanks