In order to change data for a number of Contacts, export the data, make all of the changes and then re-import. Following are the steps:
* Choose Contacts fom the Left Navigation pane and then click on the Export to Excel option on the Ribbon
* In the Dialog box, choose a Static worksheet with records from this page option
* Click on the Make this data available for re-importing by including required column headings. This will export all of the required fields.
* Enter your signature in the Description.
* You can now make changes to the existing Contact entries or add some Contact entries and import the file back into CRM.