You need at least one more adult that is linked in your family and friends and will be at the meal.
When you get to the screen to assign the lead on the reservation, you can assign the first one you make to this other adult before you make one for yourself. For instance, when we needed 2 reservations overlapping for Space 220 lounge, I searched for the 3 person first, assigned it to my husband's account, and then went back and made a the 2 person ADR work myself as the lead. I do my reservations on a browser and you can just change the drop down. I'm not sure about the app.
Once the other person is the lead, they have control over changing or cancelling the ADR but it's still your credit card on the line for the cancellation fee. So, make sure you trust the 3rd to manage the reservation if needed.
ETA: don't list anyone other than the lead when you're making reservations. If you list yourself as the 2nd on a reservation, then the system won't let you make another adr overlapping.