If you are a full time undergraduate student who started in September, you will graduate during the summer graduation period. If you are completing resits you will be able to graduate as normal, provided you have achieved 60 credits at level 6 in your final year (normally this equates to two completed units) as you have enough credits for a Bachelors without honours.
If your programme of study finishes later than May, you will attend a ceremony in the following summer.
If you are a postgraduate student, you will need to complete your full award to be able to attend ceremonies. If you accept an exit award and leave the University with a Postgraduate Certificate or Postgraduate Diploma, you could attend the graduation to accept that award. However, you would not then be able to continue your studies to gain a higher award.