How to delete selected tables using persistentStoreCoordinator

I'm currently working on an IOS app which is already developed using objective-C. I have added a module where users when login store details about the user. But as the app is already having some code, when I press the logout button it deletes all the entities from the database. For this they are using something like the code below.

NSManagedObjectContext *managedObjectContext = [self managedObjectContext];

NSError *error = nil;

// retrieve the store URL

NSURL *storeURL = [[managedObjectContext persistentStoreCoordinator] URLForPersistentStore:[[[managedObjectContext persistentStoreCoordinator] persistentStores] lastObject]];

// lock the current context

[managedObjectContext lock];

[managedObjectContext reset];//to drop pending changes

//delete the store from the current managedObjectContext

if ([[managedObjectContext persistentStoreCoordinator] removePersistentStore:[[[managedObjectContext persistentStoreCoordinator] persistentStores] lastObject] error:&error]){

    // remove the file containing the data

    [[NSFileManager defaultManager] removeItemAtURL:storeURL error:&error];

    //recreate the store like in the  appDelegate method

    [[managedObjectContext persistentStoreCoordinator] addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error];//recreates the persistent store

}

[managedObjectContext unlock];

By keeping the break points, I understood that they are retrieving the url of the database and deleting it and re-creating it. Lets say they have 3 tables A,B and C, I want to delete A & B but not C. Reference- Persistent Store Coordinator

Is my understanding correct? How can I achieve this?

TIA

I did something like below. Correct me If I'm wrong with my approach.

    - (void) deleteData {

        NSManagedObjectContext *managedObjectContext = [self managedObjectContext];
        NSError *error = nil;

        [managedObjectContext lock];
        [managedObjectContext reset];
        NSPersistentStoreCoordinator *psc = [managedObjectContext persistentStoreCoordinator];
        NSManagedObjectModel *managedModel = [psc managedObjectModel];
        NSArray *allEntityNames = [managedModel.entitiesByName allKeys];

        for(NSString *entityName in allEntityNames)
        {
//I wanted to delete all objects except for one table
            if(![entityName isEqual:switchAccountsTableName])
            {
                NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]init];
                NSEntityDescription *entity = [NSEntityDescription entityForName:entityName inManagedObjectContext:managedObjectContext];
                [fetchRequest setEntity:entity];
                NSError *objError = nil;
                NSArray *fetchedObjects = [managedObjectContext executeFetchRequest:fetchRequest error:&objError];
                if(fetchedObjects == nil)
                {
                    NSLog(@"Logout- Couldnt delete entity objects");
                }
                for(NSManagedObject *entityObj in fetchedObjects)
                {
                    [managedObjectContext deleteObject:entityObj];
                }
            }
        }
        [managedObjectContext save:&error];
        [managedObjectContext unlock];
    }