The Symbol Service feature is designed to simplify access to the different debugger features provided for symbols. Most facilities available for symbols are also available through this feature.
Symbol Service from the VLISP menu bar, or click the Symbol Service button on the Debug toolbar. 
The Symbol Service dialog box contains the following components:
If the symbol you specified is a protected symbol, the Value field will be read-only. To remove protection, clear the Protect Assign check box. See About Symbol Flags (AutoLISP) for more information on Protect Assign.
Use the OK and Cancel buttons to close the dialog box and to continue working in VLISP.