When you unapply an erroneous application, the program creates and posts correcting entries to all entries including all G/L posting derived from the application, such as payment discount and currency gains/losses. The program will also reopen the entries that were closed by the application.
Open the 
Customer Card
window or the Vendor Card
window.
Browse to the relevant customer and click Customer, Ledger Entries. Or browse to the relevant vendor and click Vendor, Ledger Entries.
Select the relevant ledger entry and click Functions, Unapply Entries.
Alternatively, click Entry, Detailed Ledger Entry. Select the entry with type Application and then click Functions, Unapply Entries.
Fill in the fields in the header and then click Unapply.
If an entry has been applied by more than one application entry, you must unapply the latest application entry first. The program automatically offers the latest entry.
Applying Customer Ledger Entries
Applying Vendor Ledger Entries