You can search the bookings list through with several filters. Within the tag filters -> filter type you can specify the parameter of your search:
<?xml version="1.0" encoding="UTF-8"?>
<envelope>
<header>
<actor>test</actor>
<user>test</user>
<password>test</password>
<version>1.0.0</version>
<timestamp>20200501170000</timestamp>
</header>
<query type="listall" product="bookings" >
<filters>
<filter type="booking" from="2009-03-27" to="2009-04-01"/>
<filter type="services" from="" to=""/>
<filter type="lastmodified" from="" to=""/>
<filter type="customer" code=""/>
<filter type="dossier" number=""/>
</filters>
</query>
</envelope>