Booking Several Appointments: Show Which Ones Must Happen in Sequence

A customer selects three services and sees three friendly lists of open times. They pick whatever suits each, and the page says confirmed. Then it turns out the second service can only follow the first. The slots were never independent. This article proposes a customer facing flow that exposes sequence dependencies up front. It is an editorial example with invented services, not a description of any observed client.

The artifact: a sequence note on the selection screen

When a customer selects more than one service, the selection summary shows each service with a relationship label: Independent, Must follow, or Must be same visit. A short sentence explains it. Booking times are offered only after those relationships are shown.

Inputs

Imagine a made up studio offering Consultation, Fitting, and Collection. Your rules, which you must set yourself and may differ in your business: Fitting must follow Consultation, Collection must follow Fitting, and the gap between them is a range you define. Each service also has a duration and a provider group. You need those rules written down as data, not kept in someone's head.

Decision branches

Customer selects only independent services: offer slot lists separately, and say each can be booked on its own.
Customer selects services with a Must follow relationship: offer a combined choice. Pick the first service time, then show only the times that respect the rule for the next.
Customer selects a later service without its prerequisite: ask whether they have already completed the earlier step. If yes, accept a self reported note for staff to confirm. If no, offer to add it. Whether you allow self reporting is your decision.
Services that must be same visit: show one combined slot and its total duration, not separate lists.
No combined sequence exists in the displayed period: say that plainly and offer a later period or a contact route, instead of offering slots that break the rule.

Stop conditions

Stop confirming the booking if any chosen time violates a stated relationship, if one of the times was released by someone else while the customer was choosing, or if the rules for a selected service are missing. Show what happened and let the customer choose again. Never confirm part of a chain without saying the rest is unconfirmed.

Also decide what happens when one appointment in a confirmed chain is cancelled. Show the customer the dependent ones before they confirm the cancellation, and let them choose to move or cancel those too.

Worked example

The customer selects Consultation, Fitting, Collection. The summary reads: Consultation first. Fitting must follow Consultation. Collection must follow Fitting. Please choose your times in this order.

They pick a Consultation time. The Fitting list now shows only later times that fit the rule. They choose one, and Collection follows the same way. The final screen lists all three with dates, marks the order, and states: These appointments depend on each other. If one changes, we will ask about the others.

If the customer later cancels the Fitting, the page warns that Collection depends on it and asks whether to move both.

Wording tips

Use everyday words: first, then, after. Avoid technical phrases like dependency. Show times in the customer's local format and name the date, not only the weekday.

Acceptance test

Set up the three sample services with the rules above and test with a person who has not seen the flow.

Select all three. Confirm the sequence note appears before any time list.
Choose a Consultation time and confirm Fitting shows only valid later times.
Try to reach Collection without Fitting. Confirm the page asks about the prerequisite instead of showing free slots.
Make the rules leave no valid time in the displayed period. Confirm a clear message and a way forward.
Release a chosen slot in test while the customer is mid selection. Confirm the final step refuses and does not confirm partially.
Cancel the middle appointment and confirm the dependent one is surfaced before anything changes.
Select two independent services and confirm they are presented as independent.

Pass if the tester can say, without prompting, which appointment must come first and what happens if one moves.

Conclusion

Availability of a slot is not the same as availability of a plan. Show the relationships, offer times in order, and refuse partial confirmation, so a customer never discovers the dependency after saying yes.