Hello Prasanna,
For cases where LOCATION would be blank, you can add an entry to the decision table with the LOCATION field left blank. Note that there is a difference in leaving a column of a decision table blank and entering a null value explicitly. In the former case, it would just disregard the condition column (i.e. no check against that column whatever be the context value, blank or not) whereas in the latter, it would specifically look for a blank value in the context for that condition column.