closing a line on By the Gig plan

I have a By the Gig plan with two lines. I now want to "close" one of the two lines. I want to keep the other line, thus keep my By the Gig plan. The line I want to "close" was originally added to take advantage of a "free phone" offer and the phone is now fully paid off and I have received all the bill credits. The phone number on that line was ported in by me when the line was added. I don't really use that line and number and thus want to "close" it.

I have a couple of questions about "closing" the line.

• If I simply "close" the line, I assume the number (that I originally ported in to Xfinity Mobile) will be lost to me and reclaimed by Xfinity Mobile or whatever system.
• If I port out the number to a different mobile provider, will that automatically "close" that line on my By the Gig plan or do I have to take some additional actions to "close" the line?
• Is there any difference between explicitly "closing" the line vs. porting out the number to another mobile provider?
• Can I access the functionality to either simply "close" the line or porting the number out on xfinity.com/mobile?