DECLARE @table_to_drop sysname = 'Customers'

DECLARE cur_fk CURSOR FOR
  SELECT [name] fk_name, object_name(parent_object_id) tbl_name
  FROM sys.foreign_keys
  WHERE referenced_object_id = object_id(@table_to_drop)

DECLARE @fk_name sysname,
  @tbl_name sysname,
  @sql nvarchar(512)

OPEN cur_fk
FETCH NEXT FROM cur_fk INTO @fk_name, @tbl_name
WHILE @@FETCH_STATUS = 0 BEGIN
  SET @sql = 'alter table ' + @tbl_name + ' drop constraint ' + @fk_name
  EXEC sp_executesql @sql
  FETCH NEXT FROM cur_fk INTO @fk_name, @tbl_name
END
CLOSE cur_fk
DEALLOCATE cur_fk