As the manager, you have the ability to RSVP for an event on behalf of a volunteer. This can be done individually or in bulk for multiple volunteers. 

To RSVP on behalf of a volunteer, go to Events

 Click on the event that you are signing someone else up for

Choose the shift, then click on Sign Up (If you already RSVP'ed yourself, this button will say Confirmed)

Click on Choose an existing volunteer

 Select the name of the volunteer in the Select Volunteer dropdown, then click on Sign Up.

To RSVP on behalf of multiple volunteers, go to Organizer Dashboard > Volunteers. Check the volunteers who should be included in your event RSVP. Then use the Choose an action dropdown to select "Bulk RSVP to an Event" and click Run. 

On the next screen, choose the event and shift that you want to RSVP for on behalf of the volunteers. 

Review the list of volunteers and confirm that you want to finish processing the bulk RSVP. 

Once the RSVP is processed, you will return to the Volunteers page and see a confirmation message on your screen.