IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'clitelefone') AND COL_LENGTH('[dbo].[clitelefone]', 'fone') IS NOT NULL
BEGIN
  ALTER TABLE [dbo].[clitelefone] ALTER COLUMN fone VARCHAR(20) NULL;
END

IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'clicontato') AND COL_LENGTH('[dbo].[clicontato]', 'fone') IS NOT NULL
BEGIN
  ALTER TABLE [dbo].[clicontato] ALTER COLUMN fone VARCHAR(20) NULL;
END