First you need to set up an extension to send calls to the external number. Could use a phantom ext for this. So create the ext...then you can manually forward the ext to outside number, but I don't recommend this because once the call is sent you lose control, can't bring it back to business voice mail. Better to set up a USER for that extension and use DYNAMIC EXTENSION EXPRESS with the number set up as HOME, to ring simultaneously with phantom. Set up a VMail for the phantom and unanswered calls will be pulled back into VM, where caller can leave message or press 0 to go somewhere else. Then you'll set one of the DIGIT TRANSLATIONS in your auto attendant announcement to go there. If you're not familiar with this we can provide more detailed instructions.
For scheduling you'll create a STAR app (Voice Processing/Devices/Applications). The steps you enter will hunt top to bottom looking for a match. So the default destination will typically be where your calls go when you're closed (more about this later), with the steps above being for other cases such as NORMAL DAY and JULY 4...point each of these to where you want calls to go during that condition, and remember to put NORMAL near the bottom, maybe 19 or 20, so there's room for exceptions above it. Then program your main inbound trunk group to ring to this STAR.
Last thing about this (but you'll really do it BEFORE creating the schedule): steps can only point to other applications, never an extension. So your NORMAL might point to your daytime auto attendant, that's fine, but if you want it to go to a person or hunt you'll need to create another Call Routing Announcement, remove the default day and night greetings, and set DIGIT TRANSLATION/TIMEOUT to the extension...and that's exactly what you'll create for the new PHANTOM EXTENSION that points to the night 800 number.
