code: func (o *InvitationManager) Remove(globalID string, username string, searchString string) error {
  	qry := bson.M{
  		"organization": globalID,
  		"$or": []bson.M{
  			{"user": username},
  			{"emailaddress": searchString},
  			{"phonenumber": searchString},
  		},
  	}
  	return o.collection.Remove(qry)
  }
docs: // Remove removes an invitation