Here is a recap about the booking flow using the EVALUATE method.
REQUEST
<envelope>
<header>
<actor>xxx</actor>
<user>xxx</user>
<password>xxx</password>
<version>1.6.3</version>
<timestamp>20191114140000</timestamp>
</header>
<query type="availability" product="hotel">
<nationality>US</nationality>
<filters>
<filter>AVAILONLY</filter>
<filter>BESTARRANGMENT</filter>
</filters>
<checkin date="2020-01-05"/>
<checkout date="2020-01-08"/>
<hotel id="5936"/>
<hotel id="126576"/>
<details>
<room type="sgl" required="1"/>
</details>
</query>
</envelope>
RESPONSE
<envelope>
<header>
<version>1.6.3</version>
<timestamp>20191114152551</timestamp>
</header>
<response type="availability" product="hotel">
<search number="100043251493109" time="1.13" />
<nights number="3" />
<checkin date="2020-01-05" />
<checkout date="2020-01-08" />
<hotels total="2">
<hotel code="5936" name="CONRAD NEW YORK MIDTOWN" stars="5" location="01" address="151 West 54th Street, 10019" promo="false" city="NYC">
[...]
<agreement id="0xa9.5936.10160.RO.X.MjMzZTg5.DX-GR.RO.NOR.OWRhYWI2.ROO" available="true" room_basis="RO" meal_basis="X" ctype="10160" c_type="10160" room_type="Deluxe Guest Room" is_dynamic="false" currency="EUR" deadline="2019-11-13" total="912.00" total_gross="912.00" original_total="912.00" special="false">
<remarks>
<remark text="ROOM ONLY"/>
</remarks>
<room type="sgl" required="1" occupancy="1">
<price from="2020-01-05" to="2020-01-06">
<roomprice nett="304.00" gross="304.00"/>
</price>
<price from="2020-01-06" to="2020-01-07">
<roomprice nett="304.00" gross="304.00"/>
</price>
<price from="2020-01-07" to="2020-01-08">
<roomprice nett="304.00" gross="304.00"/>
</price>
</room>
</agreement>
[...]
</hotel>
</hotels>
</response>
</envelope>
REQUEST
<envelope>
<header>
<actor>xxx</actor>
<user>xxx</user>
<password>xxx</password>
<version>1.6.3</version>
<timestamp>20191114140000</timestamp>
</header>
<query type="availability" product="hotel">
<search number="100043251493109" agreement="0xa9.5936.10160.RO.X.MjMzZTg5.DX-GR.RO.NOR.OWRhYWI2.ROO" price="912.00"/>
<nationality>US</nationality>
<filters>
<filter>AVAILONLY</filter>
<filter>BESTARRANGMENT</filter>
</filters>
<checkin date="2020-01-05"/>
<checkout date="2020-01-08"/>
<hotel id="5936"/>
<details>
<room type="sgl" required="1"/>
</details>
</query>
</envelope>
RESPONSE
<envelope>
<header>
<version>1.6.3</version>
<timestamp>20191114152806</timestamp>
</header>
<response type="availability" product="hotel">
<search number="100043251552044" time="2.84" />
<nights number="3" />
<evaluate>
<result code="ok" option_blocked="true"/>
</evaluate>
<checkin date="2020-01-05" />
<checkout date="2020-01-08" />
<hotels total="1">
<hotel code="5936" name="CONRAD NEW YORK MIDTOWN" stars="5" location="01" address="151 West 54th Street, 10019" promo="false" city="NYC">
<agreement id="0xa9.5936.10160.RO.X.MjMzZTg5.DX-GR.RO.NOR.OWRhYWI2.ROO" available="true" room_basis="RO" meal_basis="X" ctype="10160" c_type="10160" room_type="Deluxe Guest Room" is_dynamic="false" currency="EUR" deadline="2019-12-29" total="912.00" total_gross="912.00" original_total="912.00" special="false">
<deadline date="2019-12-29 18:00:00" value="2019-12-29 18:00:00"/>
<policies>
<policy from="2019-12-29 18:00:00" percentage="96.96" />
</policies>
<deadline_remarks>
<remark text="Car park YES (with additional debit notes) 65.00 USD Per unit/night." />
</deadline_remarks>
<remarks>
<remark text="Car park YES (with additional debit notes) 65.00 USD Per unit/night."/>
<remark text="ROOM ONLY"/>
</remarks>
<room type="sgl" required="1" occupancy="1">
<price from="2020-01-05" to="2020-01-06">
<roomprice nett="304.00" gross="304.00"/>
</price>
<price from="2020-01-06" to="2020-01-07">
<roomprice nett="304.00" gross="304.00"/>
</price>
<price from="2020-01-07" to="2020-01-08">
<roomprice nett="304.00" gross="304.00"/>
</price>
</room>
</agreement>
</hotel>
</hotels>
</response>
</envelope>
You will receive the evaluate tag within the response. Please notice you will also get the actual cancellation policies already in this stage.
REQUEST
<envelope>
<header>
<actor>xxx</actor>
<user>xxx</user>
<password>xxx</password>
<version>1.6.3</version>
<timestamp>20191114140000</timestamp>
</header>
<query type="book" product="hotel">
<search number="100043251552044"/>
<synchronous value="false"/>
<nationality>US</nationality>
<checkin date="2020-01-05"/>
<checkout date="2020-01-08"/>
<city code="NYC"/>
<availonly value="true" />
<hotel code="5936" agreement="0xa9.5936.10160.RO.X.MjMzZTg5.DX-GR.RO.NOR.OWRhYWI2.ROO"/>
<reference code="BOOK2019-12345"/>
<responses>
<to url="http://www.yoursite.com/yourprogram.cgi"/>
<to url="mailto://your.address@yoursite.com"/>
</responses>
<details>
<room type="sgl" extrabed="false" cot="false">
<pax leader="true" title="MR" name="MARIO" surname="ROSSI"/>
</room>
</details>
</query>
</envelope>
So, in order to summarize: