Umno information chief Tan Sri Annuar Musa said on Monday that Parti Pribumi Bersatu Malaysia vice-president Datuk Seri Mukhriz Mahathir is welcomed to rejoin Umno if he harbours any ambitions to become the prime minister.Annuar told reporters that even Gua Musang MP Tengku Razaleigh Hamzah had previously quit to form Semangat 46 but later rejoined the party.