IF EXISTS( 
SELECT * FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = 'publ_Tenants' AND COLUMN_NAME = 'Tenants_BankingDetails_AccountNumber'
AND DATA_TYPE = 'int')
BEGIN
    ALTER TABLE publ_Tenants 
    ALTER COLUMN Tenants_BankingDetails_AccountNumber NVARCHAR(MAX) NULL;
END