Index: GridScheduler/GridScheduler/GSProgramGrid.h
===================================================================
--- GridScheduler/GridScheduler/GSProgramGrid.h
+++ GridScheduler/GridScheduler/GSProgramGrid.h
@@ -30,13 +30,16 @@
 /// The grid wants to be resized
 -(void)programGridWantsNewFrame:(CGRect)newFrame;
 
+/// The program grid needs reloading
+-(void)programGridNeedsReload;
+
 @end
 
 /*
  * @class GSProgramGrid
  * @discussion UI control for the programs grid.
  */
-@interface GSProgramGrid : UIView<GSProgramViewDelegate>
+@interface GSProgramGrid : UIView<GSProgramViewDelegate, UIAlertViewDelegate>
 
 /// Views to be laid out on the grid
 @property(nonatomic, readonly) NSMutableArray* programViews;
Index: GridScheduler/GridScheduler/GSProgramGrid.m
===================================================================
--- GridScheduler/GridScheduler/GSProgramGrid.m
+++ GridScheduler/GridScheduler/GSProgramGrid.m
@@ -11,6 +11,8 @@
 #import "GSProgramGridPlaceholderOverlay.h"
 #import "NSString+GSString.h"
 #import "UIView+MLScreenshot.h"
+#import "GSNetworking+ProgramSlot.h"
+#import "GSProgramSlot.h"
 
 /// Seconds in a minute
 const double minutes = 60.0;
@@ -104,6 +106,19 @@
     
 }
 
+/// shows an alert to the user indicating there is a conflict
+- (void) showConflictMessage {
+    UIAlertView* alert =
+    [[UIAlertView alloc] initWithTitle:@"Conflicting changes"
+                               message:@"It seems someone else made some changes over the same part of the grid, at the same time as you. We need to reload the grid to continue."
+                              delegate:self cancelButtonTitle:@"OK"
+                     otherButtonTitles:nil];
+    
+    [alert show];
+}
+
+
+
 #pragma mark - Content layout
 
 /// Returns the Y coordinate for a given time
@@ -235,14 +250,37 @@
     
     programView.day = column;
     programView.start = [self timeForRow:row];
-    [self layoutProgram:programView];
+    
+    NSArray* deletedProgramIds = [self layoutProgram:programView];
  
-    // TODO: save
-
-}
-
-/// Lays out a program on the correct spot
--(void)layoutProgram:(GSProgramView*)programView {
+    // Saves the operation on the backend
+    GSProgramSlot* newProgramSlot = [GSProgramSlot new];
+    newProgramSlot.programCode = programView.programIdentifier;
+    newProgramSlot.programSlotId = programView.slotIdentifier;
+    newProgramSlot.start = programView.start;
+    newProgramSlot.duration = programView.duration;
+    
+    [[GSNetworking sharedInstance] submitChanges:@[newProgramSlot]
+                                      andDeletes:deletedProgramIds
+                                         andNews:@[]
+                                    withCallback:^(BOOL success, BOOL conflict, NSArray *finalIds) {
+                                        
+                                        assert(success);
+                                        
+                                        if (conflict) {
+                                            [self showConflictMessage];
+                                        }
+                                        
+                                    }];
+
+}
+
+/* @discussion Lays out a program on the correct spot
+ * @return An array with the slot IDs of the removed and overlapped programs
+ */
+-(NSArray*)layoutProgram:(GSProgramView*)programView {
+    
+    NSMutableArray* ret = [NSMutableArray array];
     
     // Move all overlapped views out of the grid
     for (GSProgramView* viewToRemove in self.programViews) {
@@ -252,15 +290,16 @@
                 viewToRemove.start < programView.start + programView.duration) ||
                 (viewToRemove.start < programView.start &&
                 viewToRemove.start + viewToRemove.duration > programView.start)) {
-                [self.delegate programGridDidMoveProgramViewOutOfGrid:viewToRemove];
+                    [ret addObject:viewToRemove.slotIdentifier];
+                    [self.delegate programGridDidMoveProgramViewOutOfGrid:viewToRemove];
             }
         }
     }
     
-    
     [self addSubview:programView];
     programView.frame = [self rectForTime:programView.start duration:programView.duration andDay:programView.day];
     
+    return ret;
 }
 
 -(void)programView:(GSProgramView *)programView expandTo:(CGPoint)vector {
@@ -276,22 +315,44 @@
     
     int copies = programView.frame.size.width / columnWidth;
     
-    // Expand to other days
+    // Program slot IDs to be deleted
+    NSMutableArray* deletes = [NSMutableArray array];
+    
+    // Expand to this and other days
     for (int delta=0; delta < copies; delta++) {
         
         // Creates new program for copy days
         GSProgramView* program = programView;
         
         if (delta > 0) {
-            // TODO: copy
             program = [program copy];
             [self addSubview:program];
         }
         
         program.day += delta;
         
-        [self layoutProgram:program];
+        [deletes addObjectsFromArray:[self layoutProgram:program]];
     }
+
+    // Saves the operation on the backend
+    GSProgramSlot* changedProgramSlot = [GSProgramSlot new];
+    changedProgramSlot.programCode = programView.programIdentifier;
+    changedProgramSlot.programSlotId = programView.slotIdentifier;
+    changedProgramSlot.start = programView.start;
+    changedProgramSlot.duration = programView.duration;
+    
+    [[GSNetworking sharedInstance] submitChanges:@[changedProgramSlot]
+                                      andDeletes:deletes
+                                         andNews:@[]
+                                    withCallback:^(BOOL success, BOOL conflict, NSArray *finalIds) {
+                                        
+                                        assert(success);
+                                        
+                                        if (conflict) {
+                                            [self showConflictMessage];
+                                        }
+                                        
+                                    }];
     
 }
 
@@ -351,6 +412,12 @@
     
 }
 
+#pragma mark - UIAlertViewDelegate methods
+
+-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
+    [self.delegate programGridNeedsReload];
+}
+
 #pragma mark - Properties
 
 -(NSMutableArray *)programViews {
Index: GridScheduler/GridScheduler/GSViewController.m
===================================================================
--- GridScheduler/GridScheduler/GSViewController.m
+++ GridScheduler/GridScheduler/GSViewController.m
@@ -277,6 +277,10 @@
     return pv;
 }
 
+-(void)programGridNeedsReload {
+    [self loadWeek];
+}
+
 -(void)programGridWantsNewFrame:(CGRect)newFrame {
     
     if (!CGRectEqualToRect(newFrame, CGRectNull)) {