>Which is a best way to use the table. Aviod message Alies is already use
>thanks

You should use private datasessions in most of your forms. Thus, a table opened in one form won't (usually) interfere with another form.

If you want to use a table very briefly, you can let VFP assign the alias:

select 0
use MyTable again && VFP will assign some alias
...
use

Or, you can assign it a specific alias for a specific purpose; here, you may also want to check whether it is already opened:

if not used("client_lookup")
  use client again in 0 alias client_lookup order ClientId
endif
select client_lookup