disk offline due to signature collision

I cloned my existing hd to a larger size in case the first drive failed. Both drives work when installed alone. When either is used as a secondary external , attachment by usb, the ext is not recognized and gives the signature conflict in disk management. disk part shows they have identical signatures and if I change the id or right click to change offline to online, the disk will be read as a secondary drive. But, the new sig makes it unbootable as a primary drive, defeating the purpose of creating the clone. My question is, if the sig has been changed so that the drive is not bootable, and I no longer have the first drive to see what the sig should be, is there a program that will find and correct the sig to make the drive bootable again? Is it possible to do a system repair or boot repair from a win 7 disk to fix this?

When you install a disk Windows edited a signature to the drive do it knows what it is as you cloned you need to use disk part go change one signature

Thanks for the reply. Not trying to use 2 bootables on the same machine, but thought I could use the clone as backup storage or to transfer files, only to find out that I can't unless I change the signature of the drive, and then it is no longer bootable. Many google threads recommend right click<select online, which works, but makes the drive no longer bootable. I am trying to find out if the newly non-bootable drive with a changed signature can be repaired if I don't know the original sig for whatever reason.

How did you change signatures with disk part?

I did not change the signatures yet. I realized if I did so that the disk won't be bootable. Again, I am only fact finding and asking that , if I did change the signatures, like many people have by right click>online in disk mgt, and did not know the correct signature to change it back, will a disk repair or other software repair this issue?

The signature is just that a signature so it know what the drive is nothing to do with booting or diskmanagement

How to Change the Disk Signature of a Drive Without Losing Existing Data or Reformatting (howtohaven.com)

Thank you jumanji and samuria for your replies. You both have misunderstood my question. I know the disk1 clone will not boot if I change its signature and don't know to use disk part write down the original signature before I change it. This has happened to those with the disk offline message in disk management who were instructed to right click>online to get access to disk1. They were not told to use disk part to write down the sig, so if they then tried to use disk1 as a bootable disk0, they would no longer have a bootable disk.
My disk1 is a clone of disk0 with the same sig id. If I mounted disk1 and made it online as a secondary disk, and I know nothing of signatures, and if then disk0 has a major malfunction and self destructs, I might say, no problem, I have the clone to use as a bootable disk, as if nothing ever happened. But, guess what- it won't boot because I unknowingly changed its sig.
In that situation, is all hope lost fixing the clone to boot, or can the sig be repaired by loading the win7 repair disk, or by some software that is out there that fixes disk signatures?
Hopefully, I have stated my question clearly this time.

Yours is a hyphothetical question. Why? If you had a signature collision you would change the unique ID of only one drive. Why should you change the unique ids of both the drives?

Anyway to answer your hyphothetical question:

If I don't know what the original unique ID of the two drives that had a signature collision and I had changed the unique ids of both those drives to some random unique ids ( I should be a maverick to do that), then as far as I know there is no way you can get the original Unique id. I would be learning something new if one finds that unique id :).