I received this (translated) email today from cp.pt, as we have reservations to travel by train from Porto to Lisbon on May 30. Luckily, several weeks ago I made bus reservations for the same trip/day.
“We inform you that, due to the strike called by the SFRCI, SINFA and SNTSF unions, for the period between 12:00 a.m. and 11:59 p.m. on May 31, 2023, strong disturbances in rail traffic are expected, in all services, with possible impact on the days before and after the strike period, on May 30 and June 1.
If minimum services are defined by the Arbitral Court, this information will be updated.
Customers who already have tickets purchased to travel on trains of the Alfa Pendular, Intercidades, International, InterRegional and Regional services, will be allowed a refund, in the total amount of the ticket purchased, or their free exchange for another train of the same category and in the same class.
The refund or exchange can be made on myCP in the "Your tickets" area (for tickets purchased at the Online Ticket Office and CP App) up to 15 minutes before the departure of the train from the customer's station of origin, or at the ticket offices.
After this period, and up to 10 days after the end of the strike, a refund can be requested by completing the online contact form "Refund for Delay or Suppression", with the sending of the scan of the original of the ticket.
We are sorry for the inconvenience caused.
We are at your disposal for any clarification or suggestion through the form or the Hotline 808 109 110 (cost of a call to the national fixed network)”