Value in a Drop Down once selected should not be shown (based on a condition)

[BHUVANESH]

I have A  Invoices Column (Enum List type)....

there should be a list of invoice no ...

1,2,3,4,etc

once i selected the 1 for this time ...next time only 2,3,4,etc show...

how its possible anyone tell me

[Suvrutt_Gurjar]

In general , please try with Valid_if by subtracting list of used options from the enumlist.

So the valid_if of the enumlist column can be something like 

{Entire Enumlist Options} - (SPLIT(Table Name[Enumlist Column Name],",")-[_THISROW].[Enumlist Column])

[Steve]

Subtract values from a list - AppSheet Help