Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_28164986_4 ( date_of_appointment VARCHAR, manner_of_departure VARCHAR, team VARCHAR )

### Question ###
when was the next coach appointed after niger tornadoes fired their coach?

### Accurate SQL ###

SELECT date_of_appointment FROM table_28164986_4 WHERE manner_of_departure = "fired" AND team = "Niger Tornadoes"