I have a face down Monastery Flock card on the battlefield.
I begin my attack phase, and declare the face down Monastery Flock as an attacker.
I would like to know if, within this phase - and therefore before the assignment of combat damage - it is possible to activate the Flock's morph ability to prevent it from dying.
I asked this question because there is an apparent contradiction in the simple operation described here.
Since the face-up side has Defender, I'm afraid it cannot be declared as an attacker. Or, however, if it is declared as an attacker when it is still face down, it may not be possible to unmorph it.
In game practice, it is never said that there is (or there isn't) some note that specifies whether a given action can or cannot be executable.
Therefore, I thought that in a case like this it was right to ask experienced players what the right interpretation is.
Is this an action that can be performed without problems, or is it still an illegal action?