只此一遭,下不为例的英文

Only this time and no more.for this once but not again.I have only done that once and I shall never do it again.not to do it any more after this

• 只此一遭:    for once in one's ...
• 下不为例:    not to be taken as ...
• 只此一遭下不为例:    only this time and ...