"To have a rethink" means to reconsider or review one's thoughts, ideas, or plans. It suggests taking another look at something and potentially changing one's perspective or decision. Full definition
As a principal for global architecture megahouse Gensler, Gervais Thompkin has rethought how multi-disciplinary scientific communities collaborate, helped support a shift from post-crime forensics to pre-crime intelligence, reduced the carbon footprint (treehugger.com)
And if they can't between them overcome the mighty Rochdale, it could be worth having a rethink about our so - called squad depth. (whoframedruelfox.com)
Now for Wenger to have a rethink on his tactic or even his position. (justarsenal.com)