class Test {

  openDeleteDialog(model) {
    const modal = this.modal.open(PopupComponent, {windowClass: 'animated fadeIn'})
    modal.componentInstance.data = {...}
    return fromPromise(modal)
  }

  setCurrentIncidentType () {
    this.FormClaimDetails.controls.IdIncidentType.setValue(this.currentClaim.IdIncidentType)
  }

  changeType () {
    const model = ...

    this.claimSvc.validateClaimIncidentTypeChange(model)
      .mergeMap(result =>
        result > 0 ?
          this.openDeleteDialog(model).catch(() => of(false)) :
          of(result)
      )
      .subscribe(result => {
        if (result) {
          this.changeClaimIncidentType(model)
        } else {
          this.setCurrentIncidentType()
        }
      })
  }
}