Deleting Data Using Table Prefix

I can run a select to retrieve data using a prefix 'a' for the specific table involved. However when I try to run a delete using the same criteria it fails telling me

Msg 102, Level 15, State 1,.......Line 1

Incorrect syntax near 'a'



The Select statement looks like:

select count(*) from schema.table a where a.customer_id=1234

The Delete looks like:

delete from schema.table a where a.customer_id=1234

What am I doing wrong here? and how can I prefix the table, because the command I want to run is much more complicated than the example above and it needs the prefix