Dell XPS 15 (L521X, Mid 2012) - Manual (Page 24)

Procedure
CAUTION: To prevent damage to the memory-module connector, do not use
tools to spread the memory module securing clips.
1 Using your fingertips, carefully spread apart the securing clips on each end of the
memory-module connector until the memory module pops up.
2 Remove the memory module from the memory-module connector.
1
2
3
1 memory-module connector 2 securing clips (2)
3 memory module
24 | Removing the Memory Module(s)