Error generated when sending a message to the customer via a service request

Summary

When entering a message to send to the customer and pressing send an error is generated

Content

We have a requirement that states that if the employee sends a message to the customer the SR status should change from New to In Progress. The following error was generated when pressing send in the Messages section in the Service Request screen:

"You cannot lock this record because it is already locked by another user."

I have defined the following script:

if (isAttributeChanged('ChannelTypeCd') && StatusCd=='ORA_SVC_NEW')
setAttribute('StatusCd','ORA_SVC_INPROGRESS') 
return true;

The field to change is Status and the value is ORA_SVC_INPROGRESS.