Please reply by return post.
返事をするさま
I beg you will answer by return of post.
to give one a favourable answer
(意味の二様に取れる返事なら)to give an equivocal answer―(漠然とした返事なら)―give a vague answer―(言を左右に托した返事なら)―give an evasive answer―(煮え切れない返事なら)―give a dubious answer―(言質を避けるような返事なら)―make a non-committal reply.
ひっくり返すこと
Please give me a response.