Could you have an authorized signer on a personal CD?

Personally, I would require it to be accomplished through a power of attorney. Most CD contracts are not set up in a manner to easily allow authorized signers.

I would think it would depend on how your account agreement reads. We do not allow this.

I agree with rlcarey, the idea of a convenience signer or agent does not fit with a time deposit. Only as an example, I would point out the Florida statute that authorizes convenience signers excludes their use on time deposits. A power of attorney is more appropriate and less likely to involve you in discussions about a third party's actions.