We all know that updating webservice table field in Custom_tables to “Y” opens the entity for access through the webservices, but can you ask CRM administrator to fire query to do this? Absolutely not. There is relatively simpler way to do this from CRM which is as follows.
A)    Log In to CRM
B)    Go to Administration à Customizationà <Select your Primary or Secondary Entity>
C)    Click on External Access tab

D) Click on the Change button
E) Select ‘Yes’ option from Web Servicefield
F) Click on the Save button