Approver Delegation

Two part question:

APPROVERS: Is there a way to autho-delegate a backup approver on proofs when the original approver is away on vacation as not to hold up the proofing approval process.

OR

ASSIGNED TO A TASK TO SEND A PROOF OUT FOR APPROVAL: Is there a way to delegate a backup person to replace the existing person assigned to an APPROVAL TASK (to send out a proof for approval) so it does this automatically rather than have Workfront recognies the Calendar vacation time blocked off by the originally assigned person and compensates by extending / adding extra days to the due date).