reset FormControl input

i’m using angular 5 and i need to know how can i reset somme input, not all input on submit

sForm = new FormGroup({
    Form: new FormGroup({
      pro: new FormControl('')
    }),
    contactForm: new FormGroup({
      client: new FormControl(this.client),
      lastName: new FormControl(''),
      name: new FormControl(''),
      email: new FormControl(''),
      mobile: new FormControl(''),
      cmd: new FormControl('')

    })
  });

Answer

below code will reset only clientName. Please try

    resetSome() {
        this.souscrireForm.reset({
            Form: {...this.souscrireForm.get('Form').value},
            contactForm: { 
                ...this.souscrireForm.get('contactForm').value,
                clientName: null
            }
        });  
    }