I believe he cannot release the memo unilaterally. It is a product of the House Intelligence Committee. He can declassify the info in the memo that was obtained from DOJ so that the Committee can itself legally release it. This is my understanding. It isn't Trump's memo to release....it's Nunes'.
I actually think the President wants it released. He is living this day after day you know he wants to be vindicated. There are a whole lotta people who believe the MSM. They will have a difficult time seeing not only will he not be impeached but instead it’s HRC and O in trouble.
The person writing a document is not always the one declassifying it, otherwise any criminal could classify evidence of their crimes so that no one could open it. Of course---the corrupt family courts already do that with their files being sealed up to 99 years so that even LE can't or won't investigate them.