when you ask for something, propose to give back something

That means, if you say you are going to be coming in later than before, you need to specify what you're going to do to make that up, leave the office late, or work extra time after hours etc.

Bottomline your schedule cannot be out of line with the rest of the staff. And my guess is your manager is not happy with your productivity, your interactions with other poeple in the office, your attitude, or something.