How does one go about doing this without resorting to re-format and fresh install?
 
For the record, the WIN 7 partition is a legit/genuine install and is scheduled to be upgraded to WIN 10.

Sounds like you're in the same boat as me, Bapu.  I take it you want to install WinX on the XP partition, not over Win7?  Although, I'm still struggling with the privacy thing.

I swear I looked at this thread an hour or so ago and the first post was different. I am still not sure what it is you are trying to do, what you already have on the drive or system, what drives you have in the machine etc. Unless you have a Windows 7 image that you can load onto the partition formerly known as XP, I do not see how you are going to get it there without a fresh install. And unless you understand how the boot manager is working, you risk killing your multiboot system by doing anything to existing partitions. 

I want to get rid of XP and become a single boot system using the WIN 7 partition (that is genuine and is scheduled for the WIN 10 upgrade).
 
As a plus, after I get rid of the XP partition I'd like to give that partition back the WIN 7 partition "before" I make the WIN 10 upgrade.
 

slart, if you are on the forum from a computer (not a phone or tab) you would see that indeed from the OP time (3 hours ago) I edited the OP 1 hour ago in an attempt to point out that did NOT want a dual boot system any more.
 

So you have a single drive that is dual booting Win XP and Win 7, and no other operating systems bootable on the machine, and you want to remove the XP partition, create a single partition on the disk that will boot Win 7 and then do an upgrade installation of Win 10 over the Win 7 partition?
 
http://www.sevenforums.com/tutorials/210983-dual-boot-delete-os.html
 
Windows 7 is pretty limited in its ability to enlarge a partition, so this might be useful to move your W7 partition if necessary.
 
http://www.partition-tool.com/personal.htm
 
 

Yes slart. That is what I want to do.

If you are a sucker for punishment and you want to keep windows partitons away from each other at all costs...check my posts here, not the simplest way:
http://forum.cakewalk.com/m/tm.aspx?m=3266521&fp=1