function _changeDate(oDate, bNoFocus){

		CalendarUtils._checkCalendarDate(oDate);

		var iYear = oDate.getYear();
		CalendarUtils._checkYearInValidRange(iYear);

		var bFocusable = true; // if date not changed it is still focusable
		if (!this.getDate() || !oDate.isSame(CalendarDate.fromLocalJSDate(this.getDate(), this.getProperty("primaryCalendarType")))) {
			var oCalDate = new CalendarDate(oDate);
			oCalDate.setDate(1); // always use begin of month
			bFocusable = this.checkDateFocusable(oDate.toLocalJSDate());

			if (!this._bNoRangeCheck && !bFocusable) {
				throw new Error("Date must be in visible date range; " + this);
			}

			this.setProperty("date", oDate.toLocalJSDate());
			this._oDate  = oCalDate;
		}

		if (this.getDomRef()) {
			if (bFocusable) {
				_focusDate.call(this, this._oDate , bNoFocus);
			}
		}

	}
@param {sap.ui.unified.calendar.CalendarDate} oDate The date to be changed
@param {boolean} bNoFocus Whether the date is focused