The purpose of the article is to study the procedural possibilities of a request and permission to change the remand in custody to a more lenient preventive measure during pre-trial criminal proceedings. The article uses the methods of system analysis, synthesis, analogy and generalization. The author concludes that a direct appeal to the court with a request to mitigate the preventive measure in the form of detention at the preliminary investigation stage within the meaning of the criminal procedure law by the participants in criminal proceedings on the part of the defense is possible at the time when the court considers the investigator's request to extend the period of detention or to change the preventive measure, or at any time during criminal proceedings in the case of a bail application. When the request for changing the preventive measure is received during the preliminary investigation from the participants in the criminal proceedings on the part of the defense during the period between court sessions on the extension of the preventive measure, the court must assess its content. If there is no evidence of a change in the grounds for changing the preventive measure in the form of detention to a more lenient one, the court shall refuse to accept the request for consideration. If the circumstances indicated in the request show a change in the grounds for applying the preventive measure, the court must adopt it and consider it under the adversarial conditions with the participation of the parties in the order of Article 108 of the Code of Criminal Procedure of the Russian Federation. In the event of refusal to satisfy the request, a repeated request on the same ground is not permitted.