"By destroying evil and replacing it with a covenant."
Right, as God said, a change of plans. He was sorry that He made man. They were wicked, and He destroyed them.
However, God declared on other occassions that He was going to destroy a wicked generation or people, and then TURNED from it (i.e. repented).
Numbers 14
11 And the LORD said unto Moses, How long will this people provoke me? and how long will it be ere they believe me, for all the signs which I have shewed among them?
12 I will smite them with the pestilence, and disinherit them, and will make of thee a greater nation and mightier than they. [The same thing God said in Exodus 32 but didn't do it!]
13 And Moses said unto the LORD, Then the Egyptians shall hear it, (for thou broughtest up this people in thy might from among them;) [The same argument Moses used in Exodus 32!]
19 Pardon, I beseech thee, the iniquity of this people according unto the greatness of thy mercy, and as thou hast forgiven this people, from Egypt even until now.
20 And the LORD said, I have pardoned according to thy word: [And not according to His declaration in passage 12 above!]
According to thy word. He pardoned according to the word of Moses. IMPOSSIBLE??? No. NOT impossible...hang on!
The Lord is angry with wicked Israel again. But this time...
Jeremiah 15
1 Then said the LORD unto me, Though Moses and Samuel stood before me, yet my mind could not be toward this people: cast them out of my sight, and let them go forth.
6 Thou hast forsaken me, saith the LORD, thou art gone backward: therefore will I stretch out my hand against thee, and destroy thee; I am weary with repenting.
Israel had become so wicked, not even Moses could change God's mind (as he had now obviously done before). God had become weary of turning away from His justified wrath.
The Israelites were doing things so wicked, that they didn't even enter the mind of God. He did not forsee such wickedness. Do not take my word for it:
Jeremiah 19
5 They [The Israelites] have built also the high places of Baal, to burn their sons with fire for burnt offerings unto Baal, which I commanded not, nor spake it, neither came it into my mind:
I am unconvinced that the scripture points to God changing his mind as a human does.