lo = CREATEOBJECT("_c")
lo.process()

DEFINE CLASS _c AS Custom
    aArray[1] = .f.
    
    PROCEDURE Process
    LOCAL laArray
        DIMENSION laArray[1]
SET STEP ON
        this.update_array(@laArray)
        this.update_array(@this.aArray)
    ENDPROC

    PROCEDURE update_array
    LPARAMETERS taArray
    EXTERNAL ARRAY taArray
        taArray[1] = "test"
    ENDPROC
ENDDEFINE