natting out
(verb) To commit to a social engagement ahead of time only to back out at the last second
"Where is Mark?"
"He said he was going to be here, but he just called and told me he remembered that he got tired."
"Fairy, he is really natting out."
"He said he was going to be here, but he just called and told me he remembered that he got tired."
"Fairy, he is really natting out."