Updating a reservation before it happens is one thing. It is quite normal to take a phone call or email before a reservation starts to add / swap / remove a bike. Perhaps extend or change the dates. Add setup information.
But then there is another type of change - the mid-rental change. Perhaps a customer takes a bike out and the chain breaks or discovers a puncture. They want a replacement bike right now to get on with their day.
These are by their nature a little different, partly due to the urgency of the need for a solution and partly because the operation itself needs to behave slightly differently.
Take the example given above. Mrs Smith takes out their bike. Discovers a problem and brings it back in with a long face and a short temper. You only have one other size S and you know it went out this morning too. Sweat begins to build.
Then you spot the other size S and you breathe a sigh of relief. You quickly check it over, send the customer on their way and update BRM accordingly.
Here is what the bookings looked like yesterday:
(Both your size S of this bike type are booked and overlapping).
But here is what your reservations look like when the problem with the Mrs Smith bike is detected:
Luckily Mr Brown came back a little early and is checked in. Due to the time to set up Mrs Smith and send her on her way she was also late. But there is still reservation overlap.
But BRM will let you do the swap at 9:26am because at that moment the other bike has been checked in and is available. It doesn't use the start time of the Smith rental - it uses the actual time now to determine if the swap is viable.
You will see an event like this in your reservation event history, indicating that a mid-rental swap has occurred.
Here are the other mid-rental scenarios that BRM supports in this way: