Click the dashed text in the Delivery meals column of the row (e.g. "3XMonday, 2XThursday" or Empty). The Edit your delivery preferences pop-up shows a box per weekday; keep adjusting the days' worth of food per delivery until the running total shown above the boxes matches the row's days per week. Until it does, Next stays disabled and the message "You've selected a total of (N) delivery dates which exceeds the plan settings of (X). You need to enter the amount of days of deliveries made on each day." is shown in red. Click Next, choose whether existing subscribers get the new delivery pattern at renewal, and Save.

Note: this edit is not written to the Price Change Log — only price amounts are logged.