1. Open the subscription and click the date in the Subscription Dates calendar strip.
2. Click Skip This Day.
3. In Skip Day, review Update next renew day to: (pre-filled with the current renewal date; not shown when your store renews on the last delivery day) and leave Create new day? ticked if the customer should get a replacement date.
4. Click Skip Day.

The date becomes Skipped, any meals already validated on it are voided, separately paid extras on that date are refunded to the customer's wallet (you see "Day skipped. $X of already-paid extras on this date was refunded to the customer's balance."), and with Create new day? a new open date with the same days/meals/portion is added after the customer's last scheduled date. A skipped day can be reversed with Unskip This Day.