[MTBlue]

If this a unbiased random event, then your odds on future tosses are not affected by switching to tails. (Tails=Heads)

If this is a biased event i.e. Tails>Heads or Heads>Tails then switching to tails is the right choice. The chances are greater at this point that the coin is biased toward Tails instead of heads. It is possible that the event is biased toward heads just more unlikely.

There are two scenarios biased and unbiased. Biased P(T)>.5 > P(T)<.5. Unbiased P(T)=.5. Compared to heads where the Biased P(H)<.5 > P(H)>.5. Unbiased P(H)=.5

Unbiased scenarion the switch is inconsequential to the results. In the biased example the switch makes sense.