Extracting work relationship data using REST API

Summary:

I need to retrieve start date and termination data for an employee using worker REST API.But when I use the worker API ,I have to further use the link for work relationship collection to traverse to work relationship data which is a child of worker.I am able to use worker REST API using the below URL:

/hcmRestApi/resources/11.13.18.05/workers?q=PersonNumber=10013510

But I am not able to fetch work relationship data using the below REST API:

/hcmRestApi/resources/11.13.18.05/workers/{workersUniqID}/child/workRelationships/{PeriodOfServiceId}

I tried to pass person id against the field {workersUniqID} and tried to retrieve all work relationships but it is not giving me any data. Can someone help me understand how do I create a parameterized URL where I can directly retrieve start date and end date from work relationship for a worker.