This motherboard?
https://asrock.com/MB/AMD/X470 Master SLIac/index.asp
What exactly are you trying to remove?
Pull the ram away from the other side, along the ram slot, instead of trying to pull it straight up.
I just edited my post #3 to add a link to the motherboard manual.
Verify that the link is correct and the manual is indeed for your motherboard.
Before doing anything else try to provide some indication of what you are trying to remove.
Memory has two tabs.
I have seen single latch ram slots before. You slide the ram into the side that doesn't have a latch, at an angle, and then push the ram down, to engage the latch, on the opposite side. To remove, you unlatch the ram, than pull the ram away from the non latched side, at an angle, so just the opposite of installation.