Problem with Material Serial Number in Goods Receipt in SAP

The Issue

While creating the Material Master we could not activate Serial Number. We created the Purchase Order & done the Goods Receipt for the Material without Serial Number.
Later we activated the Serial Number profile for the Material and did the Good Receipt with Serial Numbers.

Now we want to reverse the first document where Material was received without serial number, but the system does not allow us to do so.

The displays the following message:
Maintain serial numbers for total quantity

We just tried to de-activate the Serial Number profile, but the system does not allow us to do that also.

The displays the following message:
Serial numbers already assigned to this material

We need to reduce the stock.

Please advice what to do?

The Solution

Method 1
1) Since you cannot remove the serial profile, you will have to create a Dummy profile e.g. ZMZZ (up to you to come up with the 4 alphanumerics).
2) In this profile, set the StkCk as Blank, procedure MMSL set it to 01 (SerUsage), 01(EqReq)
3) Once you have done the above, you can now do the necessary Inventory Movements e.g. transfer posting, GR,GI..
4) When you have you have removed the previous quantities without serial numbers, insert the proper serial profile back to the material master.
5) Perform receiving to get those quantity back in SAP while inputting new serial numbers.

Method 2
1) Instead of removing the previous quantities without serial numbers, you can try this.
2) Edit the current serial profile, set the StkCk as Blank
3) Create serial numbers according to the quantities that you do not have serial number. E.g. if you have 3 quantity without serial number, so you should create 3 serial numbers for this material.
4) Perform Transfer posting from MIGO_TR for the material from one storage location to another (you can choose to repeat the same storage location also). Input the serial numbers here. Once all is completed in this screen, check and Post.
5) All your quantities now will be serialized with status ESTO (within storage locations).

Source: http://forums.sdn.sap.com/thread.jspa?threadID=1655349&messageID=8961696#8961696