One of the response options is delegate to someone else.
<b>Delegate the invitation to someone else</b>
Click Respond > Delegate or Delegate with Comments. If Delegate options do not display, then the meeting chair has disabled delegation for this invitation.
Specify the person to whom you want to send the invitation. To select the person’s name from a directory, click the down arrow in the Who would you like to delegate this request to? field.
Click Check Schedules to check the delegate’s free time schedule and see if the delegate is available at the meeting’s time.
Select Keep me informed of updates to receive any further notices about the meeting.
I think you have to set up your delagates in advance and there should then be a presented tick box to delagate the meeting. (I think)