Times Jumbo 1010 Cryptic

[bigdave1954]

Stuck on two. 21d Opening replacing conclusion in prayer f?r?m?n

49a Resign from partnership, feeling blue s?a?d ?o?n. must be stand down but I don't get the wordplay.

Thanks

[glasman]

Foramen

[factor-fiction]

I can see the 'down' but not the 'stand', but can't think of anything better

[bigdave1954]

Hmmmm. Strange ones. Can anyone help me with the wordplay on these?

[glasman]

replacing - for
conclusion in prayer- amen

[bibblebub]

21d) for amen

49a) a partnership batting in cricket is a stand, and blue = down as in depressed