Anybody can subjectively change any word or phrase in the Bible in an attempt to alter its meaning.
But the "science" of translation is a fairly exacting one based on manuscripts that are sometimes thousands of years old. We have many, many more manuscipts of biblical text that of any other classical literature, say "Gallic Wars" or the works of Herodotus for example.
The words in the Bible are surprisingly accurate if using textual analysis because of the extreme care of scribes used throughout the centuries. Thus, especially if you want to be "scientific" you must not subsitute whatever you will for what is written there, especially if based on a whim.
When my mind’s eye reads the phrase “period of time” I change nothing. I may even ask one to look at the word “DAY”.
When we say “Day” do we mean 24 hours?
When we say “Day” do we mean those hours of DAYlight as opposed to those hours of darkness called night?
Day and Day..one word with two separate meanings, sometimes in the same sentence.
Word meanings DO change over time. Example in 2009
year 1959 Gay is someone who is a good happy soul.
year 2009 Gay is something completely different!!
Technically, a “day” IS a “period of time”