Renaming a button after user input - objective-c

Question

I am a noob with Xcode and programming in general. I have a code so that a user can click on a button "Start Date" which then brings up a pop-up date picker. I want to know how to have the button "Start Date" rename itself to the date the user selects and then also allow it to be re-edited.
Here is the code I have so far:
- (void)changeDate:(UIDatePicker *)sender {
NSLog(#"New Date: %#", sender.date);
}
- (void)removeViews:(id)object {
[[self.view viewWithTag:9] removeFromSuperview];
[[self.view viewWithTag:10] removeFromSuperview];
[[self.view viewWithTag:11] removeFromSuperview];
}
- (void)dismissDatePicker:(id)sender {
CGRect toolbarTargetFrame = CGRectMake(0, self.view.bounds.size.height, 320, 44);
CGRect datePickerTargetFrame = CGRectMake(0, self.view.bounds.size.height+44, 320, 216);
[UIView beginAnimations:#"MoveOut" context:nil];
[self.view viewWithTag:9].alpha = 0;
[self.view viewWithTag:10].frame = datePickerTargetFrame;
[self.view viewWithTag:11].frame = toolbarTargetFrame;
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:#selector(removeViews:)];
[UIView commitAnimations];
}
- (IBAction)StartDate:(UIButton *)sender {
if ([self.view viewWithTag:9]) {
return;
}
CGRect toolbarTargetFrame = CGRectMake(0, self.view.bounds.size.height-216-44, 320, 44);
CGRect datePickerTargetFrame = CGRectMake(0, self.view.bounds.size.height-216, 320, 216);
UIView *darkView = [[UIView alloc] initWithFrame:self.view.bounds];
darkView.alpha = 0;
darkView.backgroundColor = [UIColor blackColor];
darkView.tag = 9;
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(dismissDatePicker:)];
[darkView addGestureRecognizer:tapGesture];
[self.view addSubview:darkView];
UIDatePicker *datePicker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, self.view.bounds.size.height+44, 320, 216)];
datePicker.tag = 10;
datePicker.datePickerMode = UIDatePickerModeDate;
[datePicker addTarget:self action:#selector(changeDate:) forControlEvents:UIControlEventValueChanged];
[self.view addSubview:datePicker];
UIToolbar *toolBar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, self.view.bounds.size.height, 320, 44)];
toolBar.tag = 11;
toolBar.barStyle = UIBarStyleBlackTranslucent;
UIBarButtonItem *spacer = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:#selector(dismissDatePicker:)];
[toolBar setItems:[NSArray arrayWithObjects:spacer, doneButton, nil]];
[self.view addSubview:toolBar];
[UIView beginAnimations:#"MoveIn" context:nil];
toolBar.frame = toolbarTargetFrame;
datePicker.frame = datePickerTargetFrame;
darkView.alpha = 0.5;
[UIView commitAnimations];
}