If the customer has both instances configured in Serviceconfig.xml, then setting the following param, under the instance they don't want to startup from 'true' to false will only startup the instance with 'true'.
<runInstance>true</runInstance>
So, if the serviceconfig looks something like below and you do not want to Startup SailPoint, then change the 'true' to 'false' on SailPoint instance as shown below
<service id="XIC"> <run>true</run> <logPath>/users/ptran/xicmultiIns/XYGATEIC/logs</logPath> <instance id="ENG1"> <runInstance>true</runInstance> <servicePort>5500</servicePort> <hpeIP>10.20.0.36</hpeIP> <hpePort>33888</hpePort> <aliasSupport>true</aliasSupport> <debug>false</debug> <ssl>true</ssl> <xtrSSL>true</xtrSSL> <hstsMaxage>63072000</hstsMaxage> <hstsPreload>true</hstsPreload> <cmdDump>false</cmdDump> <clientID>Sailpoint</clientID> <acl> <ip>*</ip> </acl> </instance> <instance id="ENG2"> <runInstance>true</runInstance> <servicePort>5511</servicePort> <hpeIP>10.20.0.36</hpeIP> <hpePort>338888</hpePort> <aliasSupport>true</aliasSupport> <debug>false</debug> <ssl>true</ssl> <xtrSSL>true</xtrSSL> <hstsMaxage>63072000</hstsMaxage> <hstsPreload>true</hstsPreload> <cmdDump>false</cmdDump> <clientID>CyberArk</clientID> <acl> <ip>*</ip> </acl> </instance> </service>
<runInstance>true</runInstance> to <runInstance>false</runInstance>