Any executor or administrator may, at any time, by writing, filed in the district court, resign his appointment, having first settled his account and delivered up all the estate to the person whom the court shall appoint to receive the same. If, however, by reason of any delays in such settlement and delivering up of the estate, or for any other cause, the circumstances of the estate or the rights of those interested therein require it, the court may at any time before the settlement of accounts and delivering up of the estate is completed, revoke the letters of such executor or administrator, and appoint in his stead an administrator, either special or general, in the same manner as directed in relation to original letters of administration. The liability of the outgoing executor or administrator, or of the sureties on his bond, shall not be in any manner discharged, released or affected by such appointment or resignation.