TAP Portugal LIS has issued this statement regarding a strike planned by its cabin staff on October 30 and November 1:

TAP Cabin Crew Union announced two separate strikes to take place on October 30 and November 1 between 12:00am and 11:59pm

Therefore, and in order to mitigate as much as possible the effects of the strike, TAP is authorizing date changes free of charge within the same cabin and tickets validity, or its refund. In order to do so, passengers should contact TAP through the Contact Center or their Travel Agencies.
Despite the situation, we inform that TAP flights operated by PGA Portugália Airlines will not be affected, as well as the flights established to operate as minimum services, available below.
All passengers with flights affected by the strike will be contacted, in order to find the best alternative.
Whenever the contact cannot be established TAP will reissue the ticket for the next available flights, keeping the schedule and dates as closer as possible to the original ones.
We suggest passengers to check their bookings here and do the online check-in if the flights are confirmed. This option is available up to 72 hours prior to departure, despite some exceptions depending on the destination.
Beforehand, and due to the high number of calls received, we apologize for any delays that may occur on the Contact Center response.

TAP regrets the situation and assures all efforts are being made to minimize the impact of this strike.