I have not much detailed information about forward handover, but I would like to mention whatever I know.
Handover term is used when an UE moves from current cell to another target cell. If both the cells are covered under same eNodeB, it called as intra-eNodeB handover. When both the cells (source cell as well as target cell) covered under different eNodeB then handover is known as inter-eNodeB.
Normal handover, In which handover command message is sent by source eNodeB to UE. Normal handover is known as backward handover.
Now, I come to your actual query.
To make forward handover happen following two conditions need to met.
1. Source eNodeB should not able to decode Ue measurement report.
2. RLF detection should be aggressively.
when these above conditions met and UE detects RLF, UE send RRC Re-establishment request message to target eNodeB. Since target eNodeB is not prepared , it responds back to UE with RRC Re-establishment Reject message. Once UE receives Re-establishment Reject message from eNodeB. It leaves RRC - Connected state and moves to RRC -IDLE state. It starts from initial cell selection procedure and sends fresh RRC Connection Request message to eNodeB. In this way , UE goes to target ; this is known as forward handover.