Transfering Advance from Special GL to Normal Items
Path: Accounting - Financial Accounting - Accounts Payable - Document Entry - Down Payment - Clearing (Transaction code is F-54)
Step 1) Give Document date, Type, Company code, Vendor account and Text
Select the Process down Payments button
Step 2) Double click empty row under Transfer Posting column
Step 3) From the menu Document - Simulate to view document details
Step 4) Select the save button
we get a message below
Go and see the Vendor Account Transaction (Use t-code FBL1N)
Step 1) Give Vendor account number and Company code
Select Cleared Items radio button
Select Special GL transaction check box
Execute
We see special GL account being cleared
Step 2) Select the back arrow 
Select Open Items radio button
Select Normal Items check box
Execute
Special GL is transferred to Normal items
Path: Accounting - Financial Accounting - Accounts Payable - Document Entry - Down Payment - Clearing (Transaction code is F-54)
Select the Process down Payments button
Step 2) Double click empty row under Transfer Posting column
Step 3) From the menu Document - Simulate to view document details
Step 4) Select the save button
we get a message belowStep 1) Give Vendor account number and Company code
Select Cleared Items radio button
Select Special GL transaction check box
Execute
Select Open Items radio button
Select Normal Items check box
Execute