IF ELSE STATEMENT INSIDE SWITCH CASE

Hi everyone, I just want to ask if how i am able to make an if else statement inside a switch case. i want to execute something wherein the user may be able to choose again if he/she would like to do another transaction. for example, the user choose Yes the program will automatically display the main menu option and if the user doesn't want another the program will automatically print "Thankyou for using the program"