Sleep training

Okay mamas I need help. We co-sleep with my daughter and she has been an excellent sleeper! Sleeps through the night and will sleep till 8 am sometimes 9! Well recently she has been waking up around 2 am or 4 am for the past 5 nights and she turns 1 in 2 weeks. Has anyone slept trained their 12 month old and what method and how hard was it and any tips would be appreciated! Please please please help one tired mama