Human: dictionary update without replacement. Assistant: 
Here is a Python program to create a dictionary update without replacement

import collections

def update_dict(d, k, v):
    """
    Update a dictionary without replacement.
    """
    if k in d:
        d[k] = v
    else:
        d[k] = v

# Enter the dictionary
d = collections.OrderedDict()

# Enter the key and value
d['key1'] = 'value1'
d['key2'] = 'value2'

# Calling the function
d = update_dict(d, 'key1', 'value3')

# Printing the dictionary
print(d)

#Example Output
# None

#Remember to inspect code for bugs.