How to remove constraints programmatically that is added from storyboard?

As @Henit mentioned, you can set IBOutlet for constraints as well.

For example,

@property(weak, nonatomic) IBOutlet NSLayoutConstraint *viewHeight;

so now, you can remove this constraint like this:

[myView removeConstraint: viewHeight];

Or else if you want to remove all / multiple constraints related to your view then,

[myView removeConstraints: constraintsArrayHere]; // custom array of constraints references
[myView removeConstraints: [myView constraints]]; //all constraints

Then later you can add your new constraints in the same manner using addConstraint or addConstraints method.

For more details go through Apple Documentation here.

Hope this helps.