On the first of every month, present to the LORD a burnt offering of two young bulls, one ram and seven male lambs a year old, all without defect.
On the day of the New Moon he is to offer a young bull, six lambs and a ram, all without defect.
Ezekiel 46:6 does in fact represent a change from Numbers 28:11. The sacrificial system outlined in 45:18-46:24 differs in many aspects from the system given in the first five books of the Bible. It was a new system to go with a new temple, representing a new era in Israel's history that would have began had the Hebrews repented of their sins (43:10-11). However, the sacrificial requirements were not moral rules in and of themselves, but rituals that could be changed by God, just as the dietary laws were. The rituals did change when Christ was sacrificed and resurrected, as explained in Hebrews 9:7-10, 10:11-14:
But only the high priest entered the inner room, and that only once a year, and never without blood, which he offered for himself and for the sins the people had committed in ignorance. The Holy Spirit was showing by this that the way into the Most Holy Place had not yet been disclosed as long as the first tabernacle was still standing. This is an illustration for the present time, indicating that the gifts and sacrifices being offered were not able to clear the conscience of the worshiper. They are only a matter of food and drink and various ceremonial washings - external regulations applying until the time of the new order...
Day after day every priest stands and performs his religious duties; again and again he offers the same sacrifices, which can never take away sins. But when this priest had offered for all time one sacrifice for sins, he sat down at the right hand of God. Since that time he waits for his enemies to be made his footstool, because by one sacrifice he has made perfect forever those who are being made holy.
Laws that are merely rituals, or object lessons, can be changed by God to suit new circumstances.