:-> Drop down list

[supert8ch]

I have a workbook that has 7 columns ABC EFG. ABC are set information. EFG will represent ABC unless there is a manual input for a different item.

ABC EFG
a1 b1 c1 b2 b1 c1
a1 b2 c1 a1 b3 c1
a1 b3 c1 b1 b1 c1
b2 b1 c1 odd item
b2 b2 c1 a1 b1 c1

The data in efg has to be same as ABC and can not have dulplicate in EFG of ABC. can add item in EFG manually if needed.
If someone needs to see document I can send it to better understand.

 

[GlennUK]

That doesn't make sense. Can you try to explain what you are after in more detail? You are more likely to get responses if your query is clearly explained.