Reducing the output of AES to 64 bit Is it possible to reduce the output of AES after encryption into 64 bit with the possibility of a reversible before decryption Without any error
There is no way to reduce the output of a single AES encryption operation to 64 bits with the possibility of decryption without error.

There are however ways to use AES to build a 64-bit cryptogram that can be decrypted without error. The simplest is: encipher the constant zero with AES, keep the first 64 bits, XOR with the plaintext to get the cryptogram. Problem is, that's insecure if the AES key is used more than once.

There are ways to allow several uses with the same key:


If an initial IV setup is tolerable (e.g. the IV overhead negligible compared to many later 64-bit cryptograms delivered in order), CTR mode is fine, as noted by Thomas M. DuBuisson.
Construct a 64-bit symmetric Feistel cipher using AES encryption for the round function (AES-encipher the concatenation of the round number and 32-bit input); with 10 rounds for good measure, and perhaps using addition modulo $2^{32}$ rather than XOR for combination of the output of the round function (so that the cipher is not always an even permutation, which would be noticeable after $2^{64}-2$ plaintext/ciphertext pairs), that's a secure 64-bit block cipher. Beware however that with this method (or any 64-bit block cipher) alone, identical 64-bit plaintexts will be recognizable as identical 64-bit ciphertexts.
FFX mode is another possibility, as noted by CodesInChaos.