Yes they can, but only if you are in a conversation with them.
If you offer a booking to a professional via the messaging system and they are interested, it’s better for both parties to have an actual booking in the system to make sure that everyone agrees on the details. Without it, there is no record if the professional doesn’t show up or cancels at the last minute.
A confirmed booking also documents the rate you agreed on, the hours they are to work, and how they will be paid.
Within the messaging features that the professional sees when they are in a conversation with you, there is a link to create a booking proposal to you, the office.
It allows them to set the booking for any date and time range that doesn’t already have a confirmed booking and an hourly rate.
This booking is then proposed to you, and you will see it on your calendar and in the bookings tab.
If you agree to it, it will be treated just like a booking that you initiated.