The easiest way to do this is with gdb. Put a breakpoint on the dlopen function, and change the parameters (likely passed on the stack). RTLD_NOW is defined as 2. Simply change it by 1 (RTLD_LAZY).

To sum up, in gdb

    breakpoint dlopen
    run
    set stack_memory_address = 1
    continue

Where stack_memory_address is the address of your mode parameter.