Step 1 - Go the Fee Plan form of the Fees Module 

Step 2 - Search the Fee Plan which user wants to copy. 

Step 3 - Open the Fee Plan from the listing 

Step 4 - Select the session where the Fee Plan needs to copy 

Step 5 - Select the Save As button and give the name of the new Fee Plan 

Step 6 - After that new fee plan wil be saved 

Step 7 - Now search the Fee Plan again and do the changes as per requirement. (Like - last date, fee head amount, or head remove and add)